[RFE] Have a way to filter/ignore message from certain users

[sergiodj]

First of all, thank you very much for this bridge.

I'm trying to find a way to ignore messages from certain users. My use case is this: the Telegram group I'm bridging has the "Captcha bot" activated, and every time someone joins the group the messages sent by the bot get bridged to Matrix. I thought about simply kicking the bot from the Matrix room, but I'm not sure if that would mess something up. Instead, it would be nice to simply configure the bridge to ignore everything the captcha bot says.

I could not find anything in the docs, so I decided to open this feature request. Thanks in advance!