## Changes
Add a mechanism to load Python source locations in the Python mutator.
Previously, locations pointed to generated YAML. Now, they point to
Python sources instead. Python process outputs "locations.json"
containing locations of bundle paths, examples:
```json
{"path": "resources.jobs.job_0", "file": "resources/job_0.py", "line": 3, "column": 5}
{"path": "resources.jobs.job_0.tasks[0].task_key", "file": "resources/job_0.py", "line": 10, "column": 5}
{"path": "resources.jobs.job_1", "file": "resources/job_1.py", "line": 5, "column": 7}
```
Such locations form a tree, and we assign locations of the closest
ancestor to each `dyn.Value` based on its path. For example,
`resources.jobs.job_0.tasks[0].task_key` is located at `job_0.py:10:5`
and `resources.jobs.job_0.tasks[0].email_notifications` is located at
`job_0.py:3:5`, because we use the location of the job as the most
precise approximation.
This feature is only enabled if `experimental/python` is used.
Note: for now, we don't update locations with relative paths, because it
has a side effect in changing how these paths are resolved
## Example
```
% databricks bundle validate
Warning: job_cluster_key abc is not defined
at resources.jobs.examples.tasks[0].job_cluster_key
in resources/example.py:10:1
```
## Tests
Unit tests and manually
Gleb Kanterov