Enable searching for included templates when rendering jinja2 templates.

[aerorahul]

Description The current implementation of jinja2 rendering was unable to support include when the included template was in a location not directly under the current template directory. This PR:

• allows jinja to search for templates in paths that are provided as searchpath as well as from /
• removes the parsing of mixed jinja and other template form $( ) from function parse_j2yaml. This was a stop gap measure to allow prototyping in the DA applications. Those have now matured that this stop gap needed to be addressed holistically.
• contains some minor code cleanup where appropriate in jinja2.py and yaml_file.py. Test for the include is added.
• updates github actions versions for checkout, setup-python. Also updates the authentication to code-cov v4 that requires use of token stored as a secret.

Type of change

• [X] New feature (non-breaking change which adds functionality)
• [X] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [X] This change requires a documentation update

How Has This Been Tested?

• [X] pynorms
• [X] pytests
• [X] in a downstream DA application with robust use of include including nesting.

Checklist

• [ ] My code follows the style guidelines of this project
• [ ] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] My changes need updates to the documentation. I have made corresponding changes to the documentation
• [ ] My changes generate no new warnings
• [ ] New and existing tests pass with my changes
• [ ] Any dependent changes have been merged and published

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 84.21053% with 6 lines in your changes are missing coverage. Please review.

Project coverage is 48.87%. Comparing base (d69dbbc) to head (968cddd).

Files	Patch %	Lines
src/wxflow/jinja.py	86.20%	3 Missing and 1 partial :warning:
src/wxflow/schema.py	0.00%	1 Missing :warning:
src/wxflow/yaml_file.py	87.50%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #15 +/- ## =========================================== - Coverage 48.91% 48.87% -0.05% =========================================== Files 15 15 Lines 1429 1416 -13 Branches 305 308 +3 =========================================== - Hits 699 692 -7 + Misses 676 670 -6 Partials 54 54 ```

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