Feature/metrics DB/SQL server

An evening hack.

To be clear: this supports any DB that https://github.com/mausch/FsSql supports.

The tests are being run with SQLite.

@karaaie - what do you think?

@mausch - The example problem comes when running Logary.DB.Tests
For shipping, only on EpochTicks. Searching, below is fine.

Path = server and metric path and metric name - move to individual columns possibly.