TypeScript gets unhappy if you're mixing what it considers to be a

"namespace" with ES modules, and can end up discarding a lot of type

checking as a result. Their recommendation is that everything these days

should be modules.
Before we switched to modules, we were starting to try to namespace our

code more thoroughly, and therefore everything inside the Djblets

configForms bundle was namespaced into Djblets.Config.*.
This change makes it so we export two names for each top-level item,

Djblets.Config.* and Djblets.Config*. This allows us to import the

ConfigForms* names from djblets/configForms without getting any warnings.

Ran js-tests.
Verified that the compiled configForms index.js file only had one copy

  of the definitions for the classes but was exporting them under both

  names.