More operators for search kit

Currently searchkit supports '=' or 'LIKE '%x' but in order to start to replace some of the dashlets created by CiviReport I think more flexibility is needed - for example if I want an afform to help me find donors with a total giving Greater Than x. Another example is NOT IN - as currently on the activities dashlet

@colemanw has already added date search ranges ('this.week') etc to give some flexibility.