Fix (most) template formatting issues in phasor dynamics

[PhilipFackler]

Description

See #366

Proposed changes

Use snake_case for template parameters. and UpperCamelT for public interface types.

Checklist

• All tests pass.
• Code compiles cleanly with flags -Wall -Wpedantic -Wconversion -Wextra.
• The new code follows GridKit™ style guidelines.
• [N/A] There are unit tests for the new code.
• [N/A] The new code is documented.
• The feature branch is rebased with respect to the target branch.
• [N/A?] I have updated CHANGELOG.md to reflect the changes in this PR. If this is a minor PR that is part of a larger fix already included in the file, state so.

[PhilipFackler]

Note that this updates the style guidelines in CONTRIBUTING.md but updates the code only in PhasorDynamics.

[pelesh]

Need to resolve conflicts, otherwise good to merge.

[nkoukpaizan]

The changes look good to me.

I am slightly concerned with having inconsistent formatting in other (non phasor dynamics) modules. As long as we are planning to update the others "soon", I'm good with merging.