* command/jsonconfig: provider config marshaling enhancements
This PR fixes a bug wherein the keys in "provider_config" were the
"addrs.ProviderConfig", and therefore being overwritten for each module,
instead of the intended "addrs.AbsProviderConfig".
We realized that there was still opportunity for ambiguity, for example
if a user made a provider alias that was the same name as a module, so
we opted to use the syntax `modulename:providername(.provideralias)`
* command/json*: fixed a bug where we were attempting to lookup schemas
with the provider name, instead of provider type.
* command/show: add "module_version" to "module_calls" in config portion
of `terraform show`.
Also extended the `terraform show -json` test to run `init` so we could
add examples with modules. This does _not_ test the "module_version"
yet, but it _did_ help expose a bug in jsonplan where modules were
duplicated. This is also fixed in this PR.
* command/jsonconfig: rename version to version_constraint and
resolved_source to source.