Add data structure and repository pattern

[daogrady]

We are currently doing a lot of conversion overhead: fully qualified names are used for lookups, have parts shaved off, glued back together, etc. This PR adds an improved data structure that keeps track of each fq that has been seen before and enables easier access of the parts of the fq. I.e. a fully qualified identifier my.bookshop.Books.author contains a leading namespace (my.bookshop), the entity's name (Books) and a property access (author), which should all be conveniently accessible.