... instead of binding to LocalFiniteElement objects.

This is how binding works everywhere else, too.  In addition,
in frees us from the difficult task to always get the
appropriate LocalFiniteElement objects to bind to.

This is the basis used as interpolation weights (for geodesic
FE functions) or for interpolating in the embedding space
(for projection-based FE functions).  The basis is not actually
used yet, but it needs to be given to the class in the
constructor.

As one further step towards making LocalInterpolationRules
more like (local) functions, introduce a new method 'bind'
accepting a local finite element and a set of (local)
coefficients.  This method replaces the constructor
taking the same arguments. Instead, the local function object
now has to be default constructed.  This is just an
intermediate step, however.

Rather than a LocalFiniteElement.  This makes LocalGeodesicFEFunction
more like a dune-functions-style local function, which I think
it should be.