Improved implementation of TangentialNormalProjection

[keileg]

Projections between global coordinates and the local tangential-normal coordinate system of each fracture is currently handled by the class TangentialNormalProjection. The projection operation is implemented as a sparse matrix which to a large degree is constructed on the fly.

Two ideas for improvement:

1. When Reimplementation of Ad projection operators #1182 is implemented, it should be possible to use this also for the projections (note: this will cover the projection to tangential and normal direction, but not the full projection, as the former are slices, while the latter is a weighted sum of rows). This may require a rewrite of the class to being an Ad operator. This could in itself be a good thing, as it will enable us to do parsing etc.
2. More speculatively, it could be possible to use existing implementations of rotation operations (think Givens rotations) in the linear algebra backend to speed up the implementation.