/v1/actions/add-comment: add param expiry

[Al2Klimov]

fixes #4663

[yhabteab]

Testprotocol:
Well, until now you had to delete all the comments manually because Icinga2 was not able to delete them automatically because you couldn't enter an expiry date when you created a comment.

Command: curl -k -v -u root:icinga -H 'Accept: application/json' -X POST 'https://localhost:5665/v1/actions/add-comment' -d '{ "type": "Service", "filter": "service.name==\"ping6\"", "expiry": '$(perl -e 'print time + 30')', "author": "yonas", "comment": "Some comments here"}'

HTTP/1.1 500 Internal Server Error
Server: Icinga/v2.12.0-rc1-24-g5b7f7344d
Content-Type: application/json
Content-Length: 14

From now on you don't have to worry about these annoying comments yourself, because Icinga2 will take over for you and you only have to do one thing, namely when creating a comment don't forget to enter the expiry date.

HTTP/1.1 200 OK
Server: Icinga/v2.12.0-rc1-24-g5b7f7344d
Content-Type: application/json
Content-Length: 280

and if you look at Icinga log after the given expiry date you will get the following message..

[2020-06-19 13:32:42 +0200] information/ConfigObjectUtility: Deleted object 'example.domain!76d4612e-8b14-4c05-93a9-086387d27feb' of type 'Comment'.