[perfromance][chat] Optimize chat subscriptions

[flexsurfer]

Currently, we have lots of computations and business login inside chat subscriptions, we should move all that into events , we should have only one subscription where we get messages stream from app-db

[churik]

@flexsurfer
is the issue still relevant according to the new design implementation?

[flexsurfer]

yes

[cammellos]

Moving to discussion for now, and we can re-open when ready to be worked on