Create a generic template

[blampe]

We should create a new workflow template which does not assume anything about the underlying provider.

The contract between CI and the provider should be driven entirely by make targets. make is not necessarily the best task runner for this purpose, but it's the one we use most widely right now so we should start there.

As we build this template, keep in mind that it should eventually be able to work equally well with native providers, component providers, or bridged providers. However our initial goal is to use it with providers not currently managed by ci-mgmt.

We should use the existing bridged provider template as a starting point as this is already quite battle-tested.

Changes we should consider making to the bridged template:

• We should not assume anything about an "upstream".
• We should try to eliminate as many customization options as possible in conjunction with Allow make target customization #1131. Concretely, this means if a provider previously needed a separate action to perform e.g. some setup, we should instead try to do that as part of a make target override or we should do it inside the test itself. This is a good practice in general as it makes things easier to reproduce locally. Examples of options we likely don't need:
  • setupScript
  • docsCmd
  • preTests and extraTests
  • sshPrivateKey
• We should consolidate test steps into a reusable action.
• We should enable the lint action by default.
• generate_coverage_data should be replaced by Codecov.
• We should stop using gotestfmt.
• We should stop sharding on language (Invert build tags to improve DX #676).