Add local mode for running validations

[hannanabdul55]

Description

Currently, when the validations script (main.py) is run from the local computer, it reads a locally set event.json, a file that is present on the Github Actions runner (more details on this file is the GITHUB_EVENT_PATH environment variable here).

What we should ideally do is to link this to the main hub repository and running test_formatting.py should use the validations from this repository. One possible solution could be to add this repository as a git submodule under the code directory in the hub.

[nickreich]

Currently, the validations can only be run via a GitHub action - it cannot be configured to run locally. At some point we might want to revisit this.