Improve Enum handling for sorting options - Get-IncidentList

[rbury]

Is your feature request related to a problem? Please describe.
Enum handling of sorting parameter works on string values and contains a large number of permutations (1023)

Describe the solution you'd like
Separate ascending and descending sorting parameters into 2 Enums.
This could be handled using Enums with only 31 permutations per parameter.

Describe alternatives you've considered
Continue parsing parameter as is with string manipulation.

Additional context