Add Bundle and BundleTangent types

[artivis]

Replaces #175.
See #175 comments for a discussion around the feature.

Closes #84.
Closes #175.

Notes

• Ubuntu 16.04 is deprecated in CI. The distro is EOL and it's support will be soon dropped in github actions (that's fortunate because this PR causes a compiler internal error on 16.04)
• Bundle is disabled on MSVC-based CI. Looks like MSVC is full of issues with alias-type and it doesn't like the Rn alias (R1/R2/R3 etc...)

Original PR description

I felt compelled to take a stab at #84 and this is the result.

I believe it is functional as it is, though it could for sure use more testing. Wanted to see what you think before proceeding.

Some comments:

• Both Composite and CompositeTangent are templated on the underlying lie group type, i.e. CompositeTangent<double, SE3, R2> (and not CompositeTangent<double, SE3Tangent, R2Tangent>) is the tangent of Composite<double, SE3, R2>.
• Both types have a member function template<size_t I> get() that allows access to the individual parts via a Map. I would have preferred to inherit from std::tuple to get std::get for free but it seems like it is assumed throughout the library that all types store the underlying data as a single continuous array.
• I first wrote it for C++17 and had to work quite hard to convert it to C++11. As a result there is a replacement for C++14 std::integer_sequence and the previous C++17 fold expressions are now using this C++11 initializer_list trick.
• Some library parts are a bit unnatural for the composite type, such as the LieAlg and Transformation types. They are there so that the full interface is implemented and the tests run
• Jacobian and Transformation are block-diagonal and could potentially be represented with sparse instead of dense matrices.

[codecov]

Codecov Report

Merging #234 (361822d) into devel (436702d) will increase coverage by 0.45%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##            devel     #234      +/-   ##
==========================================
+ Coverage   97.71%   98.17%   +0.45%     
==========================================
  Files          49       55       +6     
  Lines        1532     1753     +221     
==========================================
+ Hits         1497     1721     +224     
+ Misses         35       32       -3     

[artivis]

@pettni I opened this PR as a replacement to yours #175. I initially planned on opening a PR against your fork but there are conflicts due to this branch being rebased on devel. I thus went for the lazier simpler solution.
If you're fine with that and this PR content, I'll merge it anytime soon. The main changes since last time I pinged you are listed in the PR description.

[artivis]

While I didn't get any answer, I'm going to proceed merging this PR and closes #175.