<!-- Please make sure you have read the submission guidelines before
posting an PR -->
<!--
https://github.com/nrwl/nx/blob/master/CONTRIBUTING.md#-submitting-a-pr
-->
<!-- Please make sure that your commit message follows our format -->
<!-- Example: `fix(nx): must begin with lowercase` -->
<!-- If this is a particularly complex change or feature addition, you
can request a dedicated Nx release for this pull request branch. Mention
someone from the Nx team or the `@nrwl/nx-pipelines-reviewers` and they
will confirm if the PR warrants its own release for testing purposes,
and generate it for you if appropriate. -->
## Current Behavior
<!-- This is the behavior we have today -->
Currently, we are excluding non-buildable libs from the
`@nx/js/typescript` plugin. Although that allows non-buildable projects
from have the build target being inferred it also as a side-effect
removes the `typecheck` target which is unintended. Additionally, to
breaks the pattern of being self containment that TS project solutions
brings as we were modifying the root `nx.json`
## Expected Behavior
<!-- This is the behavior we should expect with the changes in this PR
-->
1. Non-buildable libs should not have a build target.
2. Non-buildable libs should have the typecheck target.
3. Buildable libs remain unchanged and should have both a build and
typecheck target.
4. Remove the `exclude` from `nx.json` for non-buildable libs.
## Related Issue(s)
<!-- Please link the issue being fixed so it gets closed when this is
merged. -->
Fixes #