BHoM_Adapter: Adapter Id stored in Fragment refactor

[alelom]

Description:

As discussed in various occasions, including #167

we are going to introduce a new fragment interface
IAdapterId
to be placed in the Base BHoM. This interface will be for a class that has to host an id object.
We can have another look about generics here, but as we saw in some tests in the past it might be better to just refer to object or string to simplify the framework and allow the parsing to happen in the specific toolkit.

[alelom]

Reopening as incorrectly linked to #258