Enhance multiparty documentation

Both @SamMayWork and @Chengxuan raised in the last community call that setting up a multiparty setup using the Firefly CLI or standalone can be complicated and frustrating. Sam has gone through this process recently.

Due to this friction, we agreed on the call to enhance the documentation to help users setup a multiparty network. There are number of discord threads that could be used as a guideline of what we want to cover in the documentation:
- https://discord.com/channels/905194001349627914/1197628222028906696/1199467976093597786 - Deploying the multiparty contract
- https://discord.com/channels/905194001349627914/928377875827154984/1184368448881557504 - Disabling multiparty in the helm charts

And I think a general tutorial on how to set it up