deprecatedParameter moved into inputParser

The parameter deprecation methods have been moved to the
inputParser, where they are a more relevant.

Warnings regarding the deprecation of used parameters will then
happen automatically by calling the parse function.
This means that declaring a parameter as deprecated should happen
before that.

There is one disadvantage, in that this design deviates from MATLAB's `inputParser` design. So if Octave one day decides to implement a counterpart for MATLAB's version, this change has to be reverted before we can drop in the MATLAB/Octave implementation (or subclass it).