MCR-3126 OCFL filesystem

[Mewel]

Link to jira.

[sebhofmann]

I found a conceptional Problem, which leads to errors in the tiling process. The MCRTreeCopier commits and restarts database transactions. The tiling queue runs in another thread is now able to find the commited tiling jobs and now starts tiling. The ocfl transaction of the Thread in with the MCRTreeCopier did not yet commit its OCFL Transaction, so the files which should be tiled do not exist yet.
We introduced Transaction commits in the MCRTreeCopier, so that in a large upload the connection to the database is released. In my opinion the cleanest aproach would be to remove the transaction restarts from the MCRTreeCopier, to always keep the file transaction and the database transaction in sync and also prevent weird rollback errors.

Meanwhile the uploads happen in another transaction and are stored in a local directory, so the "long" transaction only runs long to upload from the mycore machine to s3, or to copy from one local to another local directory, which should not take that long.

Was already changed.