Add sanity check for multiple new episodes

[bielna]

Add a restriction not to post when a large amount (e.g. 10+) of new episodes would be submitted at once, as this is likely an error in parser (issue with Muse Asia on 2022-07-05).

Current implementation checks for gap in numbers only if the middle episode is missing. If the middle episode would be made at the same time, that check passes.

Caveat : must support release of double and triple episodes, which occasionally occur.