[new feature] add file sequences.hh with methods for easy coordinate sequence construction

With Yasp being a tensorproduct grid, one needs to construct vectors with monotonous
sequences. This file provides functionality to do so. These include rather easy locally
equidistant methods, but also more involved ones like splitting a range according to
a geometric series.
Expand the checkIfMonotonous test.

Coordinate containers with less than 2 coordinates (=1 cell)
do not make sense. This is a good position for checking that.
Rewrite as a factory.

The concept of a factory sounds suitable to keep the naming
difficulties with this feature at bay.
Rename file to factory.hh and finish the implementation
Adjust the factory to make it compatible with the latest changes in other branches.
Make new header known to the build system(s)
Add factory.hh to the sources of the doxygen documentation
[Doc] Add doxygen doc to the class itself, not only its methods
[dune.module] Next dune version will be 2.4 not 3.0.
[doc] document the template parameters of the factory
Revert changes on the test for the moment.
Merge branch 'master' into p/dominic/coordinate-sequences-helper
Use the correct grid type

The name of the coordinate type has changed.
[doc][bugfix] Correct the doxygen docu of the factory

Latex commands in doxygen are highly error-prone. Additionally,
some formatting has been improved.
[test] update the test to check the TensorYaspGridFactory too
Make all names camelCase.
Merge branch 'p/dominic/coordinate-sequences-helper'