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.
• 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.

Further comments

I still need to update the CONTRIBUTING.md.