CAY-1968 SQLSelect cleanup and omissions

* also a unit test for SQLSelect
undeprecating 'isFetchingDataRows' - at least the getter is still valid
refactoring, cleanup

* cleanup cache key generation flow for SelectQuery
* do not generate cache key for null cache strategy
unit test cleanup
ensuring non-null cache strategy
CAY-1959 Chainable API for SelectQuery
Merge remote-tracking branch 'upstream/master' into refactor-tests

Conflicts:
	cayenne-server/src/test/java/org/apache/cayenne/query/SelectByIdIT.java