should validate modules found by module providers

external modules may be invalid for various reasons (bad deployment, incorrect environment, etc.), so it is customary to examine them more closely. the traditional way to do that is to build a small test project against the module, though less thorough but faster methods are also used.

any such methods would need some parameters, e.g. headers to include and functions to call.

this test should be performed right after a module provider created a module. the next selected provider should be tried in case validation fails.