CI alignment & combination

The CI workflows for both https://github.com/ava-labs/icm-contracts and https://github.com/ava-labs/icm-services should be combined into one. Ideally the specific tasks/tests should only run if relevant files are touched in a given branch/PR.

For purpose of development & testing, this can be done on a branch with the ICM services code copied in. This branch should not be merged directly.