feat(String): add Sting Helper functions

PSConfluencePublisher/String.Tests.ps1

@@ -0,0 +1,21 @@
+#!/usr/bin/env pwsh
+$ErrorActionPreference = "Stop"
+
+BeforeAll {
+    Import-Module (Join-Path $PSScriptRoot 'PSConfluencePublisher.psd1') -Force
+}
+
+Describe 'Get-StringHash' `
+{
+    Context 'default' `
+    {
+        It 'works' `
+        {
+             $result = Get-StringHash 'foobar'
+ 
+             $result.Hash | Should -Be (
+                'C3AB8FF13720E8AD9047DD3946' + `
+                '6B3C8974E592C2FA383D4A3960714CAEF0C4F2')
+        }
+    }
+}