TOP-1330: Add configure without available resources test

This implements the following JAMA test case: https://skaoffice.jamacloud.com/perspective.req#/testCases/1137469?projectId=335.

Some additional refactoring was done to make it easier to manually specify a TANGO host when using our framework code, by encapsulating the static logic used to find and create TANGO devices into a new class TangoContext. This was needed back when this test was in notebook form, but since it's still a useful addition I kept it in this MR.