[FR]: support custom named tsconfig files, different tsconfig per target

[jbedard]

What is the current behavior?

tsconfig files must be named tsconfig.json and only a single one can be generated and used per directory

Describe the feature

Custom named tsconfig files, maybe things like tsconfig.base.json in the root.

Multiple tsconfig files in a directory such as tsconfig.json and tsconfig.tests.json.