Proxy the file upload parts to the instance who created the file when running with multiple instances to prevent errors when sticky sessions does not works.

[FIX] "requirePasswordChange" property not being saved when set to false

This reverts commit 8d9e3d72, reversing
changes made to ecc43396.

Adding the html tags makes the emails sent out by rocket.chat better compliant with standards, and lowers the chance they'll be marked as spam.

Closes #6356