atests: removed test suite which only tested functionality tested much more thoroughly elsewhere (e.g. in resource_and_variable_imports.robot and under test_libraries directory)
atest cleanup
removed test suite which was misleadingly named and contained only tests for functioanlity tested also elsewhere
atests: Continuing converting .html -> .robot (#1766).

Converted test_and_uk_settings.html -> .robot. This required some work
because this old file had tests that were already (partly) moved
elsewhere, invalid syntax on purpose, and so one.