Refactor Formulation classes to reduce duplication and over-compilation

[PhilMiller]

Additions

• Bmi_Module_Formulation.cpp created to receive code moved out of Bmi_Module_Formulation.hpp

Removals

• Duplicate implementations of get_output_header_line and get_output_line_for_timestep are moved up to Bmi_Module_Formulation from the language-specific classes
• Inclusion of language-specific adapter and formulation classes removed from files that didn't need them

Changes

• De-template Bmi_Module_Formulation from previously taking the concrete type of the underlying adapter class

Testing

1. ctest
2. CI

Checklist

• PR has an informative and human-readable title
• Changes are limited to a single goal (no scope creep)
• Code can be automatically merged (no conflicts)
• Code follows project standards (link if applicable)
• Passes all existing automated tests
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future todos are captured in comments
• Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)
• Reviewers requested with the Reviewers tool ➡️

[PhilMiller]

I recommend that this be reviewed commit-by-commit to make things much more comprehensible.

[program--]

I think @hellkite500 wants to review first before merging, but this looks great to me!