[feature] update proof-of-work to allow setting required rounds (#4186)

# Description

This updates our proof-of-work middleware, NoLLaMas, to work on a more easily configurable algorithm (thank you f0x for bringing this to my attention!). Instead of requiring that a solution with pre-determined number of '0' chars be found, it now pre-computes a result with a pre-determined nonce value that it expects the client to iterate up-to. (though with some level of jitter applied, to prevent it being too-easily gamed). This allows the user to configure roughly how many hash-encode rounds they want their clients to have to complete.

## Checklist

- [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`.

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4186
Co-authored-by: kim <grufwub@gmail.com>
Co-committed-by: kim <grufwub@gmail.com>

vendor/codeberg.org/gruf/go-bitutil/flag_test.tpl

@@ -0,0 +1,98 @@
+package bitutil_test
+
+import (
+    "strings"
+    "testing"
+
+    "codeberg.org/gruf/go-bytes"
+)
+
+{{ range $idx, $size := . }}
+
+func TestFlags{{ $size.Size }}Get(t *testing.T) {
+    var mask, flags bitutil.Flags{{ $size.Size }}
+
+    {{ range $idx := $size.Bits }}
+
+    mask = bitutil.Flags{{ $size.Size }}(1) << {{ $idx }}
+
+    flags = 0
+
+    flags |= mask
+    if !flags.Get({{ $idx }}) {
+        t.Error("failed .Get() set Flags{{ $size.Size }} bit at index {{ $idx }}")
+    }
+
+    flags = ^bitutil.Flags{{ $size.Size }}(0)
+
+    flags &= ^mask
+    if flags.Get({{ $idx }}) {
+        t.Error("failed .Get() unset Flags{{ $size.Size }} bit at index {{ $idx }}")
+    }
+
+    flags = 0
+
+    flags |= mask
+    if !flags.Get{{ $idx }}() {
+        t.Error("failed .Get{{ $idx }}() set Flags{{ $size.Size }} bit at index {{ $idx }}")
+    }
+
+    flags = ^bitutil.Flags{{ $size.Size }}(0)
+
+    flags &= ^mask
+    if flags.Get{{ $idx }}() {
+        t.Error("failed .Get{{ $idx }}() unset Flags{{ $size.Size }} bit at index {{ $idx }}")
+    }
+
+    {{ end }}
+}
+
+func TestFlags{{ $size.Size }}Set(t *testing.T) {
+    var mask, flags bitutil.Flags{{ $size.Size }}
+
+    {{ range $idx := $size.Bits }}
+
+    mask = bitutil.Flags{{ $size.Size }}(1) << {{ $idx }}
+
+    flags = 0
+
+    flags = flags.Set({{ $idx }})
+    if flags & mask == 0 {
+        t.Error("failed .Set() Flags{{ $size.Size }} bit at index {{ $idx }}")
+    }
+
+    flags = 0
+
+    flags = flags.Set{{ $idx }}()
+    if flags & mask == 0 {
+        t.Error("failed .Set{{ $idx }}() Flags{{ $size.Size }} bit at index {{ $idx }}")
+    }
+
+    {{ end }}
+}
+
+func TestFlags{{ $size.Size }}Unset(t *testing.T) {
+    var mask, flags bitutil.Flags{{ $size.Size }}
+
+    {{ range $idx := $size.Bits }}
+
+    mask = bitutil.Flags{{ $size.Size }}(1) << {{ $idx }}
+
+    flags = ^bitutil.Flags{{ $size.Size }}(0)
+
+    flags = flags.Unset({{ $idx }})
+    if flags & mask != 0 {
+        t.Error("failed .Unset() Flags{{ $size.Size }} bit at index {{ $idx }}")
+    }
+
+    flags = ^bitutil.Flags{{ $size.Size }}(0)
+
+    flags = flags.Unset{{ $idx }}()
+    if flags & mask != 0 {
+        t.Error("failed .Unset{{ $idx }}() Flags{{ $size.Size }} bit at index {{ $idx }}")
+    }
+
+    {{ end }}
+}
+
+{{ end }}