Embed Encoder struct in the Indexer and switch BuildCommit to a method

feistelrequested to merge
feistel/gitlab-elasticsearch-indexer:embed/encoder into main

Closes #62 (closed)
Closes #63 (closed)

I've kept the method call consistent with the codebase i.Encoder.tryEncodeString vs i.tryEncodeString for type embedding, let me know if I should change it

Merge request reports