Move schema_version to gitlab from ElasticIndexer project

Background

Whenever we fix some bug related to wrong elastic values in commits, blobs, or wikis we have to update the schema_version so that we can use this schema_version for reindexing the elastic documents. But since the value of schema_version is getting set in the Indexer project we have to synchronize the new release of the Indexer project. This makes the process a bit complicated and time-consuming.

Proposal

We can move the value of schema_version from the Indexer project to the Gitlab project for commits, blobs, and wikis so that we don't have to touch the Indexer project