Adding semgrep.yml for Secrets scanning and more

[hrushikeshdeshpande]

Description

Adding Semgrep.yml file as part of App&ProdSec team's initiative to onboard Semgrep for Secrets scanning and more.

Has your change been tested?

Tested on multiple of our repos.

Screenshots (if appropriate):

Types of changes

What sort of change does your code introduce/modify?

New feature (non-breaking change which adds functionality)

Checklist:

My code follows the code style of this project.