CMake Add documentation to custom defined properties

[islas]

TYPE: bug fix

KEYWORDS: compilation, cmake

SOURCE: internal

DESCRIPTION OF CHANGES:
Problem:
As noted in #2124, prior to CMake 3.23, when defining custom properties the BRIEF_DOCS and FULL_DOCS are non-optional arguments.

Solution:
Add proper documentation to the custom properties to allow minimum CMake version requirements of the project to remain the same.

ISSUE:
Addresses #2124

TESTS CONDUCTED:

1. Tested on CMake v3.20.6

RELEASE NOTE:
Add documentation to custom properties in CMake to fix compatibility with older versions.

[weiwangncar]

The regression test results:

Test Type              | Expected  | Received |  Failed
= = = = = = = = = = = = = = = = = = = = = = = =  = = = =
Number of Tests        : 23           24
Number of Builds       : 60           57
Number of Simulations  : 158           150        0
Number of Comparisons  : 95           86        0

Failed Simulations are: 
None
Which comparisons are not bit-for-bit: 
None