Move AQL examples to a new separate specification

Current AQL specification contains few examples, which we would like to extend by adding new examples for new AQL clauses. Also there is a need to add more examples, to show functionality and complexity of some edge cases - think of cartesian product, permutation issue, etc.
Moving examples outside of main AQL specification with make the later lighter, easier to read. A similar setup can be found in PROC component, where TP examples are kept separately.
This proposal was discussed in SEC meeting of 2nd Nov.