Brief summary of issue / Description of requested feature:

After running PTB for 2+ days, discord invite link was invalid

Steps to reproduce the issue / Reasons for adding feature:

1. Keep PTB running for 2+ days, for example PTB-2021-01-25-f5763
2. Click the discord chat button in main window menu. A browser opens for discord
3. Link used is https://discord.com/invite/XHNuhz5k and discord website moans:
   
4. Restart PTB anew and immediately click same button. Another link opens which is still valid.

Error output / Expected result of feature

3. Link should stay valid regardless of runtime.

Extra information, such as Mudlet version, operating system and ideas for how to solve / implement:

We had actually earlier switched from permanent links to newly generated links upon upstart for future proofing this.