Remove Mide/enDAQ-specific schemata

[StokesMIDE]

With the development of separate libraries (idelib, endaq.device), the schemata specific to Mide and/or enDAQ should be moved into them. This will establish which package's version is canon, and prevents changes to the schema from requiring the updating of two separate repos/packages.

https://github.com/MideTechnology/idelib/issues/18 copied some of them into idelib. However, our tests use mide_ide.xml, so we can't simply remove it. It might be best to make a copy in the tests folder and have the tests import it explicitly.