[WIP] Create an EM PIC code with Maxwell's eqns in wave form

[jwscook]

Description

Please include a summary of changes, motivation and context for this PR.

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change)
• New feature (non-breaking change which adds functionality)
• API change (breaks downstream workflows and requires major semver bump)
• Requires documentation updates

Testing

Please describe the tests that you ran to verify your changes and provide instructions for reproducibility. Please also list any relevant details for your test configuration.

• Test Foo in /test/path/to/file_for_test_Foo.cpp
• Description of test Foo
• Test Bar in /test/path/to/file_for_test_Bar.cpp
• Description of test Bar

Test Configuration:

• OS:
• SYCL implementation:
• MPI details:
• Hardware:

Checklist:

• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any new dependencies are automatically built for users via cmake
• I have used understandable variable names
• I have run clang-format against my *.hpp and *.cpp changes
• I have run cmake-format against my changes to CMakeLists.txt
• I have run black against changes to *.py
• I have made corresponding changes to the documentation
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings

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How-to:

1. Format C++ source code with clang-format

find ./src ./include ./test -iname \*.hpp -o -iname \*.cpp | xargs clang-format -i

2. Format cmake files with cmake-format

cmake-format -i CMakeLists.txt src/nektar/CMakeLists.txt test/CMakeLists.txt

3. Format python with black

find ./python -iname \*.py | xargs black