Bug fixes

1ab363a Translation instructions added
9db2d83 Explain max_message_size and the fact that changing the value may cause crashes
82ebf00 Ensure a sane sequence of inserted messages
f81afc2 Added handling of desc.LastSeen to protobufs
344daed Partial fix for missing LastSeen in p2p topics
7e202e8 Fixed subscription browsing (wrong topic name)
5954cd1 Fixed failure to delete user due to un-initialized auth handlers
38ae262 Mongo driver updated due to https://nvd.nist.gov/vuln/detail/CVE-2021-20329
b74e765 Send silent pushes to the message sender too (no pushes were sent before)