Drop superfluous (broken) DSL functions

[yhabteab]

Contains the following two commits:

• Drop Checkable#process_check_result() DSL function: Not sure why it's introduced in the first place, maybe for debugging purposes at the early stage of Icinga 2 dev but I failed to see an actual useful use case for it that's worth its maintenance burden. So, this commit dropped it entirely from the DSL language.
• Drop System#track_parents DSL function: No external user needs to manipulate the actual object dependency graphs. This was maybe introduced for debugging purposes at that time but if someone messes with this in prod - good luck with that. Oh, apart from that it's broken :( and doesn't track parents as its name implies but children.

fixes #10272

[julianbrost]

Drop Checkable#process_check_result() DSL function: Not sure why it's introduced in the first place

It's not documented, searching the internet also finds no mention of it that would suggest plausible use of that function.

Back when it was added, it was mentioned in the changelog though:

icinga2/CHANGELOG.md

Line 3112 in e5d0f39

* [#4443](https://github.com/icinga/icinga2/issues/4443): Implement process\_check\_result script method for the Checkable class

However, the referenced issue #4443 doesn't provide any useful context either and looks like it was created just so that there was an issue ID to reference, it was open for less than a minute after all:

Created on 2016-08-08 12:14:39 +00:00
closed on 2016-08-08 12:15:06 +00:00

Apart from that, I fail to see a plausible use-case for this function. The usual way to run DSL function as a check command is to use check_command = "dummy" with the corresponding input variables set to functions.

Drop System#track_parents DSL function: No external user needs to manipulate the actual object dependency graphs.

That function does not manipulate anything, it just allows inspecting some internals that happen to contradict the function name. Similar like the other function, it wasn't documented and searching the internet for it yields nothing relevant.