Expand jinja environment

[DavidHuber-NOAA]

Description This adds ~three~ new features to the Jinja class: 1. Template.substitute_structure is now available as a filter. This is useful for parsing jinja templates that reference multiple similar variables (e.g. ensemble member directories). A template for the ensemble members can be passed into the jinja context dictionary and used to construct the final variables based on iterators, cycle date/time, etc.

• For example, if 20 ensemble members each have data in data/YYYYMMDD/HH/analysis/mem###, one could define 'ANALYSIS_tmpl' : "data/${YMD}/{HH}/analysis/mem{MEM}", 'current_cycle': datetime.datetime(year=2024, month=5, day=3, hour=6)
• Then in the template:

~{% set cycle_YMD = to_YMD(current_cycle) %}~ ~{% set cycle_HH = strftime(current_cycle, "%H") %}~ ~{% for mem in range(1,21) %}~ ~{% set mem3 = '%03d' % mem %}~ ~{% set tmpl_dict = {'YMD': cycle_YMD, 'HH': cycle_HH, 'MEM': mem3} %}~ ~{{ ANALYSIS_tmpl | template_substitute_structure(DOLLAR_CURLY_BRACE, tmpl_dict.get) }}~ ~{% endfor %}~

1. Add the jinja.ext.do extension to Jinja. This enables {% do ... %} statements which execute a command for which the output should not be saved. A useful example is appending to a list. Since lists in Python return None, "None" would be written to the parsed jinja template in the following example: {% set a_list = [] %}{{ a_list.append("foo") }}. Instead, one can now use do:

   {% set a_list = [] %}
   {% do a_list.append("foo") %}

2. Lastly, this updates the lambda function for the add_to_datetime filter so any SilentUndefined input will return a SilentUndefined, preventing obscure failures.

This is needed for noaa-emc/global-workflow#2491 Type of change

• [x] New feature (non-breaking change which adds functionality)
• [x] This change requires a documentation update

How Has This Been Tested?

• [x] pynorms
• [x] pytests

Checklist

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

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 47.87%. Comparing base (2c48c56) to head (1873fee).

Files	Patch %	Lines
src/wxflow/jinja.py	50.00%	0 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #26 +/- ## =========================================== + Coverage 47.84% 47.87% +0.03% =========================================== Files 18 18 Lines 1649 1650 +1 Branches 335 335 =========================================== + Hits 789 790 +1 Misses 801 801 Partials 59 59 ```

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[DavidHuber-NOAA]

After a conversation with @aerorahul, I removed the Template-based filter. I will instead write a method in the Jinja class to handle substitution using regex in a separate PR.