Unit tests for DbicLink queries

[vanstyn]

Unit tests are needed for various queries generated in DbicLink-based modules (i.e. from grid views) using the existing RapidApp::Test framework

• Various MultiFilter combinations - different columns, condition types, ands vs ors, nested, etc
• Paging
• Sorting
• QuickSearch - both normal and exact modes, multiple combinations of selected columns
• total counts