Updated to new lin library

[kylekrol]

Updated lin Library

Summary of changes

• Updated the lin library to allow for:
  • Support for C++ style implicit casting in arithmetic operations (e.g. you can add a double vector to a float vector and it will automatically deduce the return type to be a double vector).
  • Restructured modular architecture to help improve compile times if only the "modules" needed by a particular translation unit are included (most of the time only #include <lin/core.hpp> is needed unless you specifically need references, generators, factorizations, etc.)
  • Has no affect to PAN specific code but now uses GTest.
  • Can be used as a platformio library dependency so we won't need to clone submodules recursively anymore (could help with CI times as well).
• Updated the GNC constants file to take advantage of the implicit casting and reworked the includes.

This PR will need to have a sister PR in flight software. However, all changes should be backwards compatible because the new lin library still has a top level lin.hpp file that includes all modules.

Ptest Effects

NA

Testing

Passing local tests (and presumably CI).

Constants

NA

Documentation Evidence

NA