Introduce negative query conditions

[gregjoy1]

Currently querying in Redical is super basic, it only allows positive conditions (to eq x and/or y). It would benefit from negative conditions too (not to eq x and/or y).

This needs to be reflected in the following places:

• redical_ical query properties
• redical_core queries indexed_property_filters
• redical_core queries query
• redical_core queries query_parser

Plus add this into various unit and integration tests.