Feature request: Configurable timeout for mutaml-runner

[WardBrian]

[jmid]

Ack! This should be relatively straightforward...

The current timeout is hardcoded here at the top: https://github.com/jmid/mutaml/blob/cb731549abbdd67f15a130df3a850d4445781127/src/runner/runner.ml#L4

I would then add a command-line option like for build-context: https://github.com/jmid/mutaml/blob/cb731549abbdd67f15a130df3a850d4445781127/src/runner/runner.ml#L33-L36

and similar logic as for build-context to let the command-line option override an environment variable, e.g., MUTAML_TIMEOUT https://github.com/jmid/mutaml/blob/cb731549abbdd67f15a130df3a850d4445781127/src/runner/runner.ml#L163-L165

Finally I would probably pass timeout as a parameter from the entry point through to run_single_test.