## Changes
Add ApplyPythonMutator, which will fork the Python subprocess and
process pipe bundle configuration through it.
It's enabled through `experimental` section, for example:
```yaml
experimental:
pydabs:
enable: true
venv_path: .venv
```
For now, it's limited to two phases in the mutator pipeline:
- `load`: adds new jobs
- `init`: adds new jobs, or modifies existing ones
It's enforced that no jobs are modified in `load` and not jobs are
deleted in `load/init`, because, otherwise, it will break existing
assumptions.
## Tests
Unit tests
## Changes
This PR adds higher-level wrappers for calling subprocesses. One of the
steps to get https://github.com/databricks/cli/pull/637 in, as
previously discussed.
The reason to add `process.Forwarded()` is to proxy Python's `input()`
calls from a child process seamlessly. Another use-case is plugging in
`less` as a pager for the list results.
## Tests
`make test`