Add support for GMAIL POP3 OAUTH2

[cyberzork]

The latest build V10.3.4341 as per the announcement today now has Gmail POP3 OAuth support

Quote: - * POP3 with OAuth for Microsoft 365 and Gmail (via manual setup)

eM Client 10.3 - Upcoming build preview

It may have seemed quiet recently when it comes to updates, but we have been making steady progress behind the scenes as we prepare for our next major release, eM Client 11. But before that, we of course have a version 10.3 update on the way, including several improvements and new features based on your feedback, which is why we couldn’t push it as a normal service update yet! We’d appreciate your help testing this version before it’s released as an official update. Highlights include: Smar…