Added smoke_tests errand

- Added src/smoke-tests submodule
- Added warden smoke_tests properties
- Run with: `bosh run errand smoke_tests_z1`

[#70397660]

Signed-off-by: David Varvel <dvarvel@pivotallabs.com>
Changed errand names to remove zone indicator.

- Only one errand can ever be run at a time

[#70397660]

Signed-off-by: David Varvel <dvarvel@pivotallabs.com>
Created a resource pool for errands

[#70397660]

Signed-off-by: David Varvel <dvarvel@pivotallabs.com>
Bump src/dea_next

Bump cloudfoundry/dea_ng:
  Matthew Sykes:
     Subtract inactive_file from memory usage ( Travis Unknown )
  phanle:
     More README.md ( Travis Success: https://travis-ci.org/cloudfoundry/dea_ng/builds/23306479 )
     Update README.md ( Travis Failed: https://travis-ci.org/cloudfoundry/dea_ng/builds/23306373 )