Qgis-plugin-tools

- Fix: Fix submodule usage detection when installed as an embedded dependency
- Fix: Consider only external calls when detecting plugin path

- Feature: New method `resources.load_ui_from_file()` to load a ui file from direct filepath
- Feature: Support subplugins. In some special cases it is wanted to include a plugin inside another. Now `resources.plugin_path()` supports this.
- Fix: Change the implementation of `resources.package_file()` to support Python 3.8
- Refactor: Changed the plugin identification logic used in `resources.plugin_path()`
- Maintenance: Updated development dependencies
- Maintenance: Test on three latest LTR release. That means we drop support for QGIS 3.16.

- Fix: Recover from `TypeError` when getting plugin path. Enables pytest-xdist usage.

- Feature: Add `exc_info` and `stack_info` parameters to message bar logger for capturing exception.

- Feature: Add api to safely load package files
- Maintenance: Updated development dependencies
- Maintenance: Added automatic release actions