[feature] Push notifications (#3587)

* Update push subscription API model to be Mastodon 4.0 compatible

* Add webpush-go dependency

# Conflicts:
#	go.sum

* Single-row table for storing instance's VAPID key pair

* Generate VAPID key pair during startup

* Add VAPID public key to instance info API

* Return VAPID public key when registering an app

* Store Web Push subscriptions in DB

* Add Web Push sender (similar to email sender)

* Add no-op push senders to most processor tests

* Test Web Push notifications from workers

* Delete Web Push subscriptions when account is deleted

* Implement push subscription API

* Linter fixes

* Update Swagger

* Fix enum to int migration

* Fix GetVAPIDKeyPair

* Create web push subscriptions table with indexes

* Log Web Push server error messages

* Send instance URL as Web Push JWT subject

* Accept any 2xx code as a success

* Fix malformed VAPID sub claim

* Use packed notification flags

* Remove unused date columns

* Add notification type for update notifications

Not used yet

* Make GetVAPIDKeyPair idempotent

and remove PutVAPIDKeyPair

* Post-rebase fixes

* go mod tidy

* Special-case 400 errors other than 408/429

Most client errors should remove the subscription.

* Improve titles, trim body to reasonable length

* Disallow cleartext HTTP for Web Push servers

* Fix lint

* Remove redundant index on unique column

Also removes redundant unique and notnull tags on ID column since these are implied by pk

* Make realsender.go more readable

* Use Tobi's style for wrapping errors

* Restore treating all 5xx codes as temporary problems

* Always load target account settings

* Stub `policy` and `standard`

* webpush.Sender: take type converter as ctor param

* Move webpush.MockSender and noopSender into testrig

1 files changed, 208 insertions, 0 deletions

diff --git a/vendor/github.com/rivo/uniseg/properties.go b/vendor/github.com/rivo/uniseg/properties.go
new file mode 100644
index 000000000..6290e6810
--- /dev/null
+++ b/vendor/github.com/rivo/uniseg/properties.go
@@ -0,0 +1,208 @@
+package uniseg
+
+// The Unicode properties as used in the various parsers. Only the ones needed
+// in the context of this package are included.
+const (
+	prXX      = 0    // Same as prAny.
+	prAny     = iota // prAny must be 0.
+	prPrepend        // Grapheme properties must come first, to reduce the number of bits stored in the state vector.
+	prCR
+	prLF
+	prControl
+	prExtend
+	prRegionalIndicator
+	prSpacingMark
+	prL
+	prV
+	prT
+	prLV
+	prLVT
+	prZWJ
+	prExtendedPictographic
+	prNewline
+	prWSegSpace
+	prDoubleQuote
+	prSingleQuote
+	prMidNumLet
+	prNumeric
+	prMidLetter
+	prMidNum
+	prExtendNumLet
+	prALetter
+	prFormat
+	prHebrewLetter
+	prKatakana
+	prSp
+	prSTerm
+	prClose
+	prSContinue
+	prATerm
+	prUpper
+	prLower
+	prSep
+	prOLetter
+	prCM
+	prBA
+	prBK
+	prSP
+	prEX
+	prQU
+	prAL
+	prPR
+	prPO
+	prOP
+	prCP
+	prIS
+	prHY
+	prSY
+	prNU
+	prCL
+	prNL
+	prGL
+	prAI
+	prBB
+	prHL
+	prSA
+	prJL
+	prJV
+	prJT
+	prNS
+	prZW
+	prB2
+	prIN
+	prWJ
+	prID
+	prEB
+	prCJ
+	prH2
+	prH3
+	prSG
+	prCB
+	prRI
+	prEM
+	prN
+	prNa
+	prA
+	prW
+	prH
+	prF
+	prEmojiPresentation
+)
+
+// Unicode General Categories. Only the ones needed in the context of this
+// package are included.
+const (
+	gcNone = iota // gcNone must be 0.
+	gcCc
+	gcZs
+	gcPo
+	gcSc
+	gcPs
+	gcPe
+	gcSm
+	gcPd
+	gcNd
+	gcLu
+	gcSk
+	gcPc
+	gcLl
+	gcSo
+	gcLo
+	gcPi
+	gcCf
+	gcNo
+	gcPf
+	gcLC
+	gcLm
+	gcMn
+	gcMe
+	gcMc
+	gcNl
+	gcZl
+	gcZp
+	gcCn
+	gcCs
+	gcCo
+)
+
+// Special code points.
+const (
+	vs15 = 0xfe0e // Variation Selector-15 (text presentation)
+	vs16 = 0xfe0f // Variation Selector-16 (emoji presentation)
+)
+
+// propertySearch performs a binary search on a property slice and returns the
+// entry whose range (start = first array element, end = second array element)
+// includes r, or an array of 0's if no such entry was found.
+func propertySearch[E interface{ [3]int | [4]int }](dictionary []E, r rune) (result E) {
+	// Run a binary search.
+	from := 0
+	to := len(dictionary)
+	for to > from {
+		middle := (from + to) / 2
+		cpRange := dictionary[middle]
+		if int(r) < cpRange[0] {
+			to = middle
+			continue
+		}
+		if int(r) > cpRange[1] {
+			from = middle + 1
+			continue
+		}
+		return cpRange
+	}
+	return
+}
+
+// property returns the Unicode property value (see constants above) of the
+// given code point.
+func property(dictionary [][3]int, r rune) int {
+	return propertySearch(dictionary, r)[2]
+}
+
+// propertyLineBreak returns the Unicode property value and General Category
+// (see constants above) of the given code point, as listed in the line break
+// code points table, while fast tracking ASCII digits and letters.
+func propertyLineBreak(r rune) (property, generalCategory int) {
+	if r >= 'a' && r <= 'z' {
+		return prAL, gcLl
+	}
+	if r >= 'A' && r <= 'Z' {
+		return prAL, gcLu
+	}
+	if r >= '0' && r <= '9' {
+		return prNU, gcNd
+	}
+	entry := propertySearch(lineBreakCodePoints, r)
+	return entry[2], entry[3]
+}
+
+// propertyGraphemes returns the Unicode grapheme cluster property value of the
+// given code point while fast tracking ASCII characters.
+func propertyGraphemes(r rune) int {
+	if r >= 0x20 && r <= 0x7e {
+		return prAny
+	}
+	if r == 0x0a {
+		return prLF
+	}
+	if r == 0x0d {
+		return prCR
+	}
+	if r >= 0 && r <= 0x1f || r == 0x7f {
+		return prControl
+	}
+	return property(graphemeCodePoints, r)
+}
+
+// propertyEastAsianWidth returns the Unicode East Asian Width property value of
+// the given code point while fast tracking ASCII characters.
+func propertyEastAsianWidth(r rune) int {
+	if r >= 0x20 && r <= 0x7e {
+		return prNa
+	}
+	if r >= 0 && r <= 0x1f || r == 0x7f {
+		return prN
+	}
+	return property(eastAsianWidth, r)
+}