Indicate is user member of guild

[Sprokof]

Hi, i added indication for is user member of guild or not

[danthe1st]

@liquiddevelopmentnet Is this needed/useful for our purposes?
I assume this refers to #451 which was created but I think we decided to not really need that.

To be honest, we don't really use GitHub issues that much.

[danthe1st]

Hi @Sprokof,
It seems like we are not really needing this feature for our purposes.
Unfortunately, our issues page is not really up-to-date.
If you still want to contribute something to this repository, you could possibly check in the Discord server.

If you think of a new (functional) change that should be done, you can also suggest it there.

If you are looking for issues you could maybe take a look at #313 but I'd still recommend asking in the Discord first.

In case you think this PR still brings significant improvement, feel free to tell us.