[GITEA] Vendor rupture dependency

- The [rupture](https://github.com/ethantkoenig/rupture) dependency was
essentially outdated in the sense it was using old version of
dependencies.
- The usage by Forgejo was rather a small portion, so that portion is
now vendored (with its tests).
- Removes old dependencies from go.sum (less dependencies is better for
reviewing what the heck we're importing). Just to note that they were
likely not being used by Go's build process (according to
https://go.dev/ref/mod#minimal-version-selection), so it's really a
matter of formal cleaning up dependencies we don't use and therefor
don't want to download and be in our go.sum.

(cherry picked from commit aa72a5f009)

Conflicts:
	go.sum
	https://codeberg.org/forgejo/forgejo/pulls/2148

modules/indexer/internal/bleve/util.go

@@ -12,7 +12,6 @@ import (
 
 	"github.com/blevesearch/bleve/v2"
 	"github.com/blevesearch/bleve/v2/index/upsidedown"
-	"github.com/ethantkoenig/rupture"
 )
 
 // openIndexer open the index at the specified path, checking for metadata
@@ -26,7 +25,7 @@ func openIndexer(path string, latestVersion int) (bleve.Index, int, error) {
 		return nil, 0, err
 	}
 
-	metadata, err := rupture.ReadIndexMetadata(path)
+	metadata, err := readIndexMetadata(path)
 	if err != nil {
 		return nil, 0, err
 	}