make E2E tests run faster

[seth127]

• run less scenarios
  • maybe move some scenarios to be unit tests that use the mocked grid
• reconfigure drone server to keep up a tiny worker node at all

As we go

• tighten up (and document, as necessary) skipping mechanism for both long and grid tests so that we can run the bbi test suite locally, but skip these tests
• add Test Id's for mrgvalidate

[seth127]

This is mostly done. Going to do a few quick tweaks to cut down unnecessary scenarios and then we're good.

• long-running one where we verify the extension of models should only run on the expansion test
• post-execution test only needs one scenario (acop)
• NMqual test only needs one scenario (acop)
• init_test.go only needs one scenario?

[shairozan]

• Restructured tests
• Cut out unnecessary scenarios
• Forced one worker to exist at all times