~cyberia/docs

Update docs
Update docs according to last congress
Merge remote-tracking branch 'origin/master'
update link to go-neb
Add postgres upgrade instructions
cert expiry alerts, add link to blackbox exporter config
update certificate inventory
Merge remote-tracking branch 'origin/master'
add lets encrypt cert inventory
update docs
Merge remote-tracking branch 'origin/master'
add btcpay host keys
Merge remote-tracking branch 'refs/remotes/origin/master'
fix formatting
make headers smoller
add to the minetest doc
mintest where things are and how to test connection
explain minetest auto updates
add minetest docs
Next