Modifying Test-DscEventLogStatus to be exportable

[ArtWDrahn]

Breaking up my commits into separate PRs without any white space changes. Should be easier to review. 👍

[dlwyatt]

There are two calls to Test-DscEventLogStatus from inside the module which should be updated to pass in the new ComputerName parameter, and we should probably also have a Credential parameter as well.

(The old code appears to have a bug; Test-DscEventLogStatus was always checking a local event log, instead of making use of the script-scope computer / credential variables. One of the many things that can shoot you in the foot when using global variables instead of parameters.)

[ArtWDrahn]

Personally I hate global variables and would much rather see them excised from this script. However that's a bigger PR and will need more validation/testing that I'm not done writing. Also not sure you guys are interested in removing them when it doesn't really get us much.

I have updated the PR with some code to pass credentials as requested.