Add C++

[KangarooKoala]

Adds the C++ side of wpilibsuite#5473.

Notes:

• This adds a const modifier on TimeInterpolatableBuffer::Sample to allow PoseEstimator::SampleAt to be const-qualified.
• This takes a different approach to the tests than the Java version. Notably, it follows the pattern of the former tests in storing the encoder readings and updating those on each iteration (instead of adding noise to the ground truth pose). It also doesn't change the standard deviations, and it doesn't use constants for the standard deviations because of the confusion from name hiding. (This can be changed if desired)
• There are also a few differences in PoseEstimationTestUtils- For example, SE2Kinematics swapped multiplication and division by dt to make the units match. A getter for the wrapped pose in SE2KinematicPrimitive was also added since other places needed it.

[KangarooKoala]

Weird that running it locally (I have a Mac) didn't catch the constexpr error.

[jlmcmchl]

The best PRs delete more code than they contribute. 👍