[chore/docs] Fix Prometheus metric names for Gin, include example Grafana dash, update docs (#4443)v0.20.0-rc1

# Description

> If this is a code change, please include a summary of what you've coded, and link to the issue(s) it closes/implements.
>
> If this is a documentation change, please briefly describe what you've changed and why.

This pull request updates some of our inconsistent metric naming, and adds an example Grafana dashboard using all the most up-to-date metrics names, and updates our docs to describe the latest way of setting up metrics.

Closes https://codeberg.org/superseriousbusiness/gotosocial/issues/4362
Closes https://codeberg.org/superseriousbusiness/gotosocial/issues/4055

## Checklist

Please put an x inside each checkbox to indicate that you've read and followed it: `[ ]` -> `[x]`

If this is a documentation change, only the first checkbox must be filled (you can delete the others if you want).

- [x] I/we have read the [GoToSocial contribution guidelines](https://codeberg.org/superseriousbusiness/gotosocial/src/branch/main/CONTRIBUTING.md).
- [x] I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
- [x] I/we have not leveraged AI to create the proposed changes.
- [x] I/we have performed a self-review of added code.
- [x] I/we have written code that is legible and maintainable by others.
- [x] I/we have commented the added code, particularly in hard-to-understand areas.
- [x] I/we have made any necessary changes to documentation.
- [ ] I/we have added tests that cover new code.
- [x] I/we have run tests and they pass locally with the changes.
- [x] I/we have run `go fmt ./...` and `golangci-lint run`.

Co-authored-by: kim <grufwub@gmail.com>
Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4443
Reviewed-by: kim <gruf@noreply.codeberg.org>
Co-authored-by: tobi <tobi.smethurst@protonmail.com>
Co-committed-by: tobi <tobi.smethurst@protonmail.com>

1 files changed, 0 insertions, 85 deletions

diff --git a/vendor/codeberg.org/gruf/go-bitutil/pack.go b/vendor/codeberg.org/gruf/go-bitutil/pack.go
deleted file mode 100644
index 2a57d3294..000000000
--- a/vendor/codeberg.org/gruf/go-bitutil/pack.go
+++ /dev/null
@@ -1,85 +0,0 @@
-package bitutil
-
-// PackInt8s will pack two signed 8bit integers into an unsigned 16bit integer.
-func PackInt8s(i1, i2 int8) uint16 {
-	const bits = 8
-	const mask = (1 << bits) - 1
-	return uint16(i1)<<bits | uint16(i2)&mask
-}
-
-// UnpackInt8s will unpack two signed 8bit integers from an unsigned 16bit integer.
-func UnpackInt8s(i uint16) (int8, int8) {
-	const bits = 8
-	const mask = (1 << bits) - 1
-	return int8(i >> bits), int8(i & mask)
-}
-
-// PackInt16s will pack two signed 16bit integers into an unsigned 32bit integer.
-func PackInt16s(i1, i2 int16) uint32 {
-	const bits = 16
-	const mask = (1 << bits) - 1
-	return uint32(i1)<<bits | uint32(i2)&mask
-}
-
-// UnpackInt16s will unpack two signed 16bit integers from an unsigned 32bit integer.
-func UnpackInt16s(i uint32) (int16, int16) {
-	const bits = 16
-	const mask = (1 << bits) - 1
-	return int16(i >> bits), int16(i & mask)
-}
-
-// PackInt32s will pack two signed 32bit integers into an unsigned 64bit integer.
-func PackInt32s(i1, i2 int32) uint64 {
-	const bits = 32
-	const mask = (1 << bits) - 1
-	return uint64(i1)<<bits | uint64(i2)&mask
-}
-
-// UnpackInt32s will unpack two signed 32bit integers from an unsigned 64bit integer.
-func UnpackInt32s(i uint64) (int32, int32) {
-	const bits = 32
-	const mask = (1 << bits) - 1
-	return int32(i >> bits), int32(i & mask)
-}
-
-// PackUint8s will pack two unsigned 8bit integers into an unsigned 16bit integer.
-func PackUint8s(u1, u2 uint8) uint16 {
-	const bits = 8
-	const mask = (1 << bits) - 1
-	return uint16(u1)<<bits | uint16(u2)&mask
-}
-
-// UnpackUint8s will unpack two unsigned 8bit integers from an unsigned 16bit integer.
-func UnpackUint8s(u uint16) (uint8, uint8) {
-	const bits = 8
-	const mask = (1 << bits) - 1
-	return uint8(u >> bits), uint8(u & mask)
-}
-
-// PackUint16s will pack two unsigned 16bit integers into an unsigned 32bit integer.
-func PackUint16s(u1, u2 uint16) uint32 {
-	const bits = 16
-	const mask = (1 << bits) - 1
-	return uint32(u1)<<bits | uint32(u2)&mask
-}
-
-// UnpackUint16s will unpack two unsigned 16bit integers from an unsigned 32bit integer.
-func UnpackUint16s(u uint32) (uint16, uint16) {
-	const bits = 16
-	const mask = (1 << bits) - 1
-	return uint16(u >> bits), uint16(u & mask)
-}
-
-// PackUint32s will pack two unsigned 32bit integers into an unsigned 64bit integer.
-func PackUint32s(u1, u2 uint32) uint64 {
-	const bits = 32
-	const mask = (1 << bits) - 1
-	return uint64(u1)<<bits | uint64(u2)&mask
-}
-
-// UnpackUint32s will unpack two unsigned 32bit integers from an unsigned 64bit integer.
-func UnpackUint32s(u uint64) (uint32, uint32) {
-	const bits = 32
-	const mask = (1 << bits) - 1
-	return uint32(u >> bits), uint32(u & mask)
-}