Add timeout param to ctx.actions.run

[jpopadak]

Description

Add timeout param to ctx.actions.run for RBE and local environment use.

• Add timeout parameter to ctx.actions.run() and ctx.actions.run_shell() Starlark API
• Add SpawnAction.Builder.setTimeout(Duration) that sets ExecutionRequirements.TIMEOUT in execution info
• Add empty-string guard to Spawns.getTimeout()
• Add unit tests for setTimeout and Starlark timeout parameter (positive, zero, null, negative, override)

Motivation

Some actions in a Remote Execution environment can take a long time and there is no way to split them up due to some third party application commands. The environment can have their own timeouts, but if a single action needs to be longer, it should be explicitly configured for that longer timeout.

Build API Changes

Does this PR affect the Build API? Yes - Starlark API

If yes, please answer the following:

1. Has this been discussed in a design doc or issue? Custom RBE timeout for non-test actions #21142
2. Is the change backward compatible? Yes - additive to something the user does not have access to change.
3. If it's a breaking change, what is the migration plan? N/A

Checklist

• I have added tests for the new use cases (if any).
• I have updated the documentation (if applicable).

Release Notes

RELNOTES[NEW]: Add parameter timeout to ctx.actions.{run,run_shell}