Should fix messed up import suggestions and simplifies all tsconfigs
through inheritance.
One main issue was that packages were inheriting `baseURL: "."` from the
root tsconfig. This caused incorrect import suggestions that start with
"packages/...".
This PR ensures that packages do not inherit this baseURL: "." property,
while ensuring the root, non-inherited tsconfig still keeps it to get
tests to work (the importMap needs it)
