🚀 [Feature]: Moved PSCredential functions to the PSCredential module (#78)

## Description

This pull request removes three PowerShell scripts related to the
management of PSCredentials. The scripts provided functionalities for
creating, restoring, and saving PSCredentials.

These functions have been moved to
[`PSCredential`](https://github.com/PSModule/PSCredential).

Removal of PSCredential management scripts:

*
[`src/functions/public/PowerShell/PSCredential/New-PSCredential.ps1`](diffhunk://#diff-760a100357d1ec9525cff0a604255efcbd0478a3a91652cdb621452c786c1160L1-L39):
Removed the script that created a PSCredential from a username and
password.
*
[`src/functions/public/PowerShell/PSCredential/Restore-PSCredential.ps1`](diffhunk://#diff-e16f68514ca98d915abb547345d2c4b510e88acadb52d56e588a043f7d9c9030L1-L42):
Removed the script that restored a PSCredential from a file.
*
[`src/functions/public/PowerShell/PSCredential/Save-PSCredential.ps1`](diffhunk://#diff-db306a63a340e6a237b8f99ceaabc235c9bb8677cb1c3bf9b9f5a0e2a0a1aaa0L1-L54):
Removed the script that saved a PSCredential to a file.

## Type of change

<!-- Use the check-boxes [x] on the options that are relevant. -->

- [ ] 📖 [Docs]
- [ ] 🪲 [Fix]
- [ ] 🩹 [Patch]
- [ ] ⚠️ [Security fix]
- [x] 🚀 [Feature]
- [ ] 🌟 [Breaking change]

## Checklist

<!-- Use the check-boxes [x] on the options that are relevant. -->

- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas

Author: MariusStorhaug

src/functions/public/PowerShell/PSCredential/New-PSCredential.ps1

@@ -5,22 +5,6 @@
 param()
 
 Describe 'Utilities' {
-    Describe 'Function: Join-URI' {
-        It "Join-Uri -Path 'https://example.com' -ChildPath 'foo' -AdditionalChildPath 'bar'" {
-            $uri = Join-Uri -Path 'https://example.com' -ChildPath 'foo' -AdditionalChildPath 'bar'
-            Write-Verbose $uri -Verbose
-            Write-Verbose "Should -Be 'https://example.com/foo/bar'" -Verbose
-            $uri | Should -Be 'https://example.com/foo/bar'
-        }
-
-        It "Join-Uri 'https://example.com/foo' '/bar/' '//baz/something/' '/test/'" {
-            $uri = Join-Uri 'https://example.com/foo' '/bar/' '//baz/something/' '/test/'
-            Write-Verbose $uri -Verbose
-            Write-Verbose "Should -Be 'https://example.com/foo/bar/baz/something/test'" -Verbose
-            $uri | Should -Be 'https://example.com/foo/bar/baz/something/test'
-        }
-    }
-
     Describe 'Function: IsNullOrEmpty' {
         It 'Returns true for $null' {
             ($null | IsNullOrEmpty -Verbose) | Should -BeTrue