Move gitea api calls in own "client" package (#78)

continue #75
close #16
- fix regression (from #34) _thanks to @crystal_
- create own gitea client package
- more logging
- add mock impl of CertDB

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: crystal <crystal@noreply.codeberg.org>
Reviewed-on: https://codeberg.org/Codeberg/pages-server/pulls/78
Reviewed-by: crapStone <crapstone@noreply.codeberg.org>

server/database/interface.go

@@ -8,8 +8,8 @@ import (
 type CertDB interface {
 	Close() error
 	Put(name string, cert *certificate.Resource) error
-	Get(name []byte) (*certificate.Resource, error)
-	Delete(key []byte) error
-	Compact() (pogreb.CompactionResult, error)
+	Get(name string) (*certificate.Resource, error)
+	Delete(key string) error
+	Compact() (string, error)
 	Items() *pogreb.ItemIterator
 }