[Modules] Update private endpoint to optionally deploy only one private DNS zone group

[eriqua]

Description

Closes #1674

• Adding multiple DNS zone groups to a single Private Endpoint is not supported (ref). Updating pe implementation to only allow one private DNS zone group.
• Each DNS zone group can support up to 5 DNS zones (ref). Updating privateDNSzoneGroups implementation to limit DNS zones to 5.
• Updating pe and privateDNSzoneGroups API version
• Updating cross referencing modules pe implementation and readmes to reflect new api and parameters

Pipeline references

For module/pipeline changes, please create and attach the status badge of your successful run.

Pipeline

Type of Change

Please delete options that are not relevant.

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Update to documentation

Checklist

• I'm sure there are no other open Pull Requests for the same update/change
• My corresponding pipelines / checks run clean and green without any errors or warnings
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (readme)
• I did format my code

[github-actions]

Unit Test Results

    1 files  ±0      1 suites  ±0   34s ⏱️ -3s
151 tests ±0  149 ✔️ ±0  2 💤 ±0  0 ❌ ±0 
152 runs  ±0  150 ✔️ ±0  2 💤 ±0  0 ❌ ±0 

Results for commit 9969a04. ± Comparison against base commit fac5bcc.

This pull request removes 2 and adds 2 tests. Note that renamed tests count towards both.

/home/runner/work/ResourceModules/ResourceModules/utilities/pipelines/staticValidation/module.tests.ps1 ‑ API version tests [All apiVersions in the template should be 'recent'].In [Microsoft.KeyVault/vaults] used resource type [privateEndpoints/privateDnsZoneGroups] should use one of the recent API version(s). Currently using [2021-05-01]
/home/runner/work/ResourceModules/ResourceModules/utilities/pipelines/staticValidation/module.tests.ps1 ‑ API version tests [All apiVersions in the template should be 'recent'].In [Microsoft.KeyVault/vaults] used resource type [privateEndpoints] should use one of the recent API version(s). Currently using [2021-05-01]

/home/runner/work/ResourceModules/ResourceModules/utilities/pipelines/staticValidation/module.tests.ps1 ‑ API version tests [All apiVersions in the template should be 'recent'].In [Microsoft.KeyVault/vaults] used resource type [privateEndpoints/privateDnsZoneGroups] should use one of the recent API version(s). Currently using [2021-08-01]
/home/runner/work/ResourceModules/ResourceModules/utilities/pipelines/staticValidation/module.tests.ps1 ‑ API version tests [All apiVersions in the template should be 'recent'].In [Microsoft.KeyVault/vaults] used resource type [privateEndpoints] should use one of the recent API version(s). Currently using [2021-08-01]

♻️ This comment has been updated with latest results.