Massive rewrite of wellness to be more flexible

  * Services can now be Procs or lambdas
  * Super flexible configuring for wellness
  * Switched to minitest as the test framework
  * Removed rspec dependency
  * Removed simplecov dependency
I feel like everything from here to L41 could be combined. The status checking and such could be condensed into the initial iteration over services. I dont think this is at all critical right nowl; everything looks like it works just fine.