Test all possible execution parameters in unit tests

Closes #185

See merge request !201

Fix energy headers in ALPINE

See merge request !206

Fix pot. energy and kick in Penning trap

See merge request !204

Vary position precision in PIC/ORB tests

Allow arbitrary field and attribute types at template level

Use new parameterization framework for rank independent testing

Update BareField unit tests
Breaks all other unit tests

Allow combinations of multiple tuples

Fix serial check and hessian unit test

Use GTEST_SKIP

Can create unit tests for mixed precision and mixed memory spaces

Optimize FFTs

See merge request !192

Enforce type uniformity

Prevent uninitialized pointers for solvers and fields

Define uniform type for fields
Fix mixed execution FFTs
Define enum to identify forward and backward FFTs