What exactly does this bridge dhcp filter in wiki?
I also have this problem in buildings that users connect routers to their apartment without asking.
I also like to know what these rules will do?
They will stop DHCP traffic if it passes through the MikroTik router. However, DHCP packets are distributed in the whole LAN, independent from the router.
As already mentioned, a manageable/smart switch is really the only way to filter out such packets, by making all devices forward packets only in the direction of your router and back (which would also effectively forbid your clients from communicating with each other at all, without the router's permission).
The alternative is simply not using DHCP, but using either IPs or PPPoE. Leave DHCP to provide settings that only lead to a single web page, which explains how to setup the connection "manually".