chore: remove `globalDotEnv` and `dotEnv` fields (#8181)
### Description
This PR removes `globalDotEnv`/`dotEnv` in favor of `globalDependencies`
and `inputs` which is now fairly ergonomic to use with the addition of
`$TURBO_DEFAULTS$`.
This PR does *not* update the corresponding JS types.
### Testing Instructions
Updated existing integration tests
