OCC command to help users recover their notifications

[nickvergessen]

that may work on the web client, (I'd never seen it, or even known of its' existence until now)
but it doesn't help the desktop apps ...

I'd think it'd be helpful to have an occ command which would be able to:

• count them (all / by user / by state?)
• enumerate the oldest (all / by user / by state?)
• ack them (one/all/by user/by date? (olderthan/newerthan/range?) )
• purge them (one/all/by user/by date? (olderthan/newerthan/range?) )

I've seen slowlog entries on my host around notifications.... which is what brought this to light for me...
(datapoint of one, and I'm not confident that this was causal or just a symptom of other issues at the time.. so I don't wanna make this a focus as it could be red-herring)

Originally posted by @wolfspyre in #122 (comment)