Chore: Prepare websocket for compressed payload

[FelberMartin]

Problem Description

To reduce the load on the server with sent websocket updates, the Artemis team decided to compress the payloads of websocket updates if the exceed a certain threshold.

This PR closes #195

Changes

• Added check for the websocket compression header and optionally decompress the websocket payload
• Added tests for both compressed and normal payloads

Steps for testing

As the compression is not yet live on any servers, we can only test that un-compressed payloads work as before.

• Go to any chat with the app
• Write a message to that chat from the webapp
• Observe that the new message is immediately displayed on the app (without the need for a refresh)

[eylulnc]

I had a some related to message deleting but could not reproduced it after the second build.
When I tried to delete a message I got the pop up for - Could not delete the message.

[FelberMartin]

I had a some related to message deleting but could not reproduced it after the second build. When I tried to delete a message I got the pop up for - Could not delete the message.

Okay that's weird, these websocket changes should actually have no effect on the deletion of messages🤔. In case you find a way to reproduce the bug, please also try whether it occurs on develop aswell.

I also tried reproducing the error but did not get an error pop up.