Fix the creation of powershell arrays in Icinga2 configuration

[RincewindsHat]

No description provided.

[LordHepipud]

Thank you for the PR. Which problem does it exactly solve?
The current implementation creates comma separated entries for PowerShell arrays. Why wrap it specifically inside @()?

[RincewindsHat]

When using the powershell-connector to circumvent the performance problems, comma separated values are not interpreted as an array and some calls to check functions will therefore not work as expected. Using the @() syntax so declare an array negates this problem in that case, since arrays are then detected as expected and properly handed to the API as an array.
If there is another (better) way to do this, I am open to suggestions.

[LordHepipud]

Thank you for the clarification. Can you please rename the variable foo too psarr and update the changelog for v.1.10.0 with the following Enhancement:

* [#534](https://github.com/Icinga/icinga-powershell-framework/pull/534) Improves Icinga and Director configuration generator, by wrapping PowerShell arrays inside `@()` instead of simply writing them comma separated

Please also update the description of this PR accordingly and squash both commits to one commit only.

Thank you in advance!

[LordHepipud]

Before I forget it: Please also add a ; behind return "@(" + psarr + ")