Fix get_item endpoint

See merge request !194

Remove the unnecessary uuid dependency along the way

Implement Schema-based File API

See merge request memri/pod!192

Implement sort order and result limits

See merge request memri/pod!191

Add tests for Schema modification

See merge request memri/pod!190

Fix Schema triggers

See merge request memri/pod!189

Old schema entry removal should
happen _before_ inserting new values.

Fix docs

See merge request memri/pod!188

Docker build improvements

See merge request memri/pod!187

Nobody used this API at this moment
because API wasn't working until 2 commits ago.

While not clean to change without deprecation warnings and all,
it should be safe to do so now.