* configs: parse provider source string during module merge
This was the smallest unit of work needed to start writing provider
source tests!
* Update configs/parser_test.go
Co-Authored-By: Alisdair McDiarmid <alisdair@users.noreply.github.com>
* configs: added map of ProviderLocalNames to configs.Module
We will need to lookup any user-supplied local names for a given FQN.
This PR adds a map of ProviderLocalNames to the Module, along with
adding tests for this and for decodeRequiredProvidersBlock.
This also introduces the appearance of support for a required_provider
"source" attribute, but ignores any user-supplied source and instead
continues to assume that addrs.NewLegacyProvider is the way to go.