[desktop] Windows signing

Summary:
Adds configuration for windows signing

• env vars for certificate file and password
• change authors field to the company name visible on the certificate

Test Plan: Build, check if the certificate is visible on the installer and the app executable. Check on other windows computers if certificate works.

Reviewers: tomek, atul

Reviewed By: tomek

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D6100