[Enhancement:] DM Responder

[David Hozic]

Summary

Create a DM responder.
The DM responder would send a fixed response when a certain keyword was used.

Basic Example

daf.client.ACCOUNT(
    ...,
    auto_responders=[
        DMResponder(keywords=["NFT"], constrains=[GuildConstraint(guild=123456789)]),
        GuildResponder(keywords=["BUY"], constrains=[ChannelConstraint(channel=2313213)], action=DMResponse(data=[])),
    ]
)

Unresolved questions

• Multiple keywords?
• Actual keywords (one word) or extended RegEx matching?

[David Hozic]

Merged with #527