Keep point/vector representations In mind.

[kellertuer]

Similar to for example the Hyperbolic manifold, a Lie group might have different representations for its points and tangent vectors. This should be also the case here

Things to keep in mind

• AbstractLieGroupPoint might be a good idea for a subtype of the ManifoldsBase.AbstractManifoldPoint – mainly to emphasise a new kind of subtypes
• AbstractLieAlgebraVector <: ManifoldsBase.TVector analogue
• we should maybe define a default type that is equivalent to just using Arrays if resonable (or PartitionArray on ProductLieGroup`)
• maybe also something like an GeneralLinearMatrix or so in a general representation in matrix form?