Add option to disable sale of new accounts

When the server is at full capacity you would need to disable
the sale of new accounts and only allow renewals. Now this option
is added under "Telegram CRM" settings menu.

Fix a bug in the usage report of the bot that resulted in a crash

Bot and duplicate client name bug fixes

- Fixed a bug where bot user could add invalid uuids
- Fixed a bug which allowed duplicate client emails with
  different letter cases
- Now /usage accepts any text that contains UUID (complete link)
- Fixed the bug where renew msg wasn't sent due to missing lang

Update the readme file and add screenshots

Fix the TG reminder bug for unlimited accounts

Broadcast message to bot added plus small UI improvements

Do not show renew btn in the bot if CRM is disabled

The renew button under usage message in the bot should be
hidden if the admin has disabled the CRM.

Try to fix release upload issue - attempt 1

Stop receiving TG updates after restart

Fixed the bug where the old telegram goroutine kept running
after restarting the panel from the settings page.

Improvements to TG bot

- Fixed a UI bug where sometimes client mgs didn't refresh
- Removed the "start" menu item
- Disabled TG message previews
- Added notification for admin when client signs up