[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, 4 insertions, 0 deletions

diff --git a/testrig/teststructs.go b/testrig/teststructs.go
index 58986bffa..7d5c3caab 100644
--- a/testrig/teststructs.go
+++ b/testrig/teststructs.go
@@ -47,6 +47,7 @@ type TestStructs struct {
 	HTTPClient          *MockHTTPClient
 	TypeConverter       *typeutils.Converter
 	EmailSender         email.Sender
+	WebPushSender       *WebPushMockSender
 	TransportController transport.Controller
 }
 
@@ -83,6 +84,7 @@ func SetupTestStructs(
 	federator := NewTestFederator(&state, transportController, mediaManager)
 	oauthServer := NewTestOauthServer(db)
 	emailSender := NewEmailSender(rTemplatePath, nil)
+	webPushSender := NewWebPushMockSender()
 
 	common := common.New(
 		&state,
@@ -101,6 +103,7 @@ func SetupTestStructs(
 		mediaManager,
 		&state,
 		emailSender,
+		webPushSender,
 		visFilter,
 		intFilter,
 	)
@@ -117,6 +120,7 @@ func SetupTestStructs(
 		HTTPClient:          httpClient,
 		TypeConverter:       typeconverter,
 		EmailSender:         emailSender,
+		WebPushSender:       webPushSender,
 		TransportController: transportController,
 	}
 }