CMake file names changed to not clash when included as submodule

[raneamri]

Description

This PR changes file names in xad/cmake to be prefixed with XAD.
This issue was discovered when trying to implement XAD as a submodule to a project that has a SetupTesting.cmake file.

Type of change

• Bug fix (non-breaking change which fixes an issue)

[coveralls]

Pull Request Test Coverage Report for Build 10492793282

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 98.727%

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Totals
Change from base Build 9981166775:	0.0%
Covered Lines:	2404
Relevant Lines:	2435

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💛 - Coveralls

[github-actions]

Test Results

    29 files  ±0      29 suites  ±0   11m 35s ⏱️ +2s
 1 312 tests ±0   1 312 ✅ ±0  0 💤 ±0  0 ❌ ±0 
38 010 runs  ±0  38 010 ✅ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit b86329f. ± Comparison against base commit 259e3cf.