[Functions Feature]: Support monorepo setup in functions deployment

[mkue]

Firebase functions don't support monorepos properly. This is why we need to use relative imports and install all dependencies specifically in the functions/ project.

By integrating this project, the problem could be solved: https://github.com/0x80/isolate-package

The goal would be to be able to specify

"@socialincome/shared": "^1.0.0"

as a dependency in the functions/package.json file and use regular imports, e.g.
import { FirestoreAdmin } from '@socialincome/shared/src/firebase/admin/FirestoreAdmin'
instead of
import { FirestoreAdmin } from '../../../../shared/src/firebase/admin/FirestoreAdmin'

More info about the problem can be found here: firebase/firebase-tools#653

[DarkMenacer]

PR Created: #526

[DarkMenacer]

I had created a fork of the original repo to solve this issue.
Now that I can create branches in the original repo, I've deleted the fork and created a branch here.
Here's the branch that contains the code to solve this issue: https://github.com/socialincome-san/public/tree/pranav/functions-isolate-package