feat(1.0): Prepare for launch

Goals:

[x] Streamline user invitation via manual invite or payment https://github.com/divyenduz/LingoParrot/issues/17
/adduser <email> works
Razorpay is postponed right now, having some issues with their Subscription API, contacted support. -- Mainly, Payment via RazorPay pending, it would look like a webhook from Razorpay
[x] Admin commands https://github.com/divyenduz/LingoParrot/issues/32
[x] State management https://github.com/divyenduz/LingoParrot/issues/24

Good to haves

[ ] Multi-language support https://github.com/divyenduz/LingoParrot/issues/5 -- Base work is done, can be done before 1.0 -- Update: Postponing to future
[ ] Don't reject publicly https://github.com/divyenduz/LingoParrot/issues/16 -- POC is done but implementation is low priority -- Update: This is not valid anymore as we don't block users in the group.
[ ] ~Edit message support~ https://github.com/divyenduz/LingoParrot/issues/15 (partially done, details on the issue) -- Not merging because can edit wrong messages
[ ] Default language source is "auto" but user configurable https://github.com/divyenduz/LingoParrot/issues/7 -- Base work is done, can be done before 1.0 -- Update: Postponing to future

divyenduz / languagelearners