[performance] overhaul struct (+ result) caching library for simplicity, performance and multiple-result lookups (#2535)

* rewrite cache library as codeberg.org/gruf/go-structr, implement in gotosocial

* use actual go-structr release version (not just commit hash)

* revert go toolchain changes (damn you go for auto changing this)

* fix go mod woes

* ensure %w is used in calls to errs.Appendf()

* fix error checking

* fix possible panic

* remove unnecessary start/stop functions, move to main Cache{} struct, add note regarding which caches require start/stop

* fix copy-paste artifact... 😇

* fix all comment copy-paste artifacts

* remove dropID() function, now we can just use slices.DeleteFunc()

* use util.Deduplicate() instead of collate(), move collate to util

* move orderByIDs() to util package and "generify"

* add a util.DeleteIf() function, use this to delete entries on failed population

* use slices.DeleteFunc() instead of util.DeleteIf() (i had the logic mixed up in my head somehow lol)

* add note about how collate differs from deduplicate

internal/federation/dereferencing/announce.go

@@ -107,19 +107,21 @@ func (d *Dereferencer) EnrichAnnounce(
 		// All good baby.
 
 	case errors.Is(err, db.ErrAlreadyExists):
+		uri := boost.URI
+
 		// DATA RACE! We likely lost out to another goroutine
 		// in a call to db.Put(Status). Look again in DB by URI.
-		boost, err = d.state.DB.GetStatusByURI(ctx, boost.URI)
+		boost, err = d.state.DB.GetStatusByURI(ctx, uri)
 		if err != nil {
-			err = gtserror.Newf(
+			return nil, gtserror.Newf(
 				"error getting boost wrapper status %s from database after race: %w",
-				boost.URI, err,
+				uri, err,
 			)
 		}
 
 	default:
 		// Proper database error.
-		err = gtserror.Newf("db error inserting status: %w", err)
+		return nil, gtserror.Newf("db error inserting status: %w", err)
 	}
 
 	return boost, err