[Feature] Avoid the old, untracked issue.

[frank-zsy]

The user or developer will create issue to PouchContainer for issue report or something. For some issues, with some reason, we cannot reproduce the issue or has it fixed. However, the issue will look like orphan in the system.

For this reason, I propose to add the functionality in the PouchRobot to close the issue if no-one comments in 30 days. If PouchContainer still has the issue, this action will let the owner know that there is one orphan need help.

[allencloud]

I think this is quite important for us to handle issues as soon as possible. However, I think 30 days is a little bit short, how about 60 days, two months? @Frankzhaopku

[frank-zsy]

@allencloud I suppose this should be configurable, I will consider this during PR review.

[frank-zsy]

For this issue, I think the following steps could do it:

1. when start the program, check all open issues and closed those whose last_updated is early than 30 days from now.
2. Start a timer to run procedure 1 every day.