feat: add database cleanup function

[ShamanthOP]

Closes #43

Added a function to remove stale documents from participants and active_pairs collection. It is scheduled to run everyday at 1:00 A.M.

Participant documents which do not have a corresponding active room and Active_pair documents older than a day gets removed by the function.

[chandansgowda]

Can we schedule it to run each and every hour or so ? Will there be any issues ? Also, @Aarush-Acharya does this cause any conflict to the discussions feature you are implementing ?

[ShamanthOP]

Can we schedule it to run each and every hour or so ? Will there be any issues ? Also, @Aarush-Acharya does this cause any conflict to the discussions feature you are implementing ?

We can but it wouldn't add any significant benifits. Since it's a background task performance isn't an issue. So executing it once a day seems right.

[chandansgowda]

@ShamanthOP If we dont do it frequently, inactive rooms will be displayed along with other rooms and users might be trying to join those.

[ShamanthOP]

@ShamanthOP If we dont do it frequently, inactive rooms will be displayed along with other rooms and users might be trying to join those.

Inactive rooms should be cleared up by the webhook receiver. We can add it here also to be super extra careful though. This PR currently only cleans participants and active_pairs collection.