refactor: adapt to nuspec requirement for gallery publishing

tools/String.psm1

@@ -0,0 +1,42 @@
+#!/usr/bin/env pwsh
+
+function Get-StringHash
+{
+    <#
+        .SYNOPSIS
+            Get hash value of a string
+
+        .DESCRIPTION
+            The Get-StringHash function is just a wrapper around the
+            Get-FileHash function and utilizes a stream for providing said
+            function with proper input values.
+
+        .OUTPUTS
+            Same as the Get-FileHash function
+
+        .EXAMPLE
+            Get-StringHash 'foobar' -Algorithm 'SHA256'
+    #>
+    Param(
+        [Parameter(Mandatory, Position = 0)] [String] $InputString,
+        [Parameter()] [String] $Algorithm = 'SHA256'
+    )
+
+    Begin
+    {
+        $stream = [IO.MemoryStream]::New()
+
+        $writer = [IO.StreamWriter]::New($stream)
+
+        $writer.Write($InputString)
+
+        $writer.Flush()
+
+        $stream.Position = 0
+    }
+
+    Process
+    {
+         Get-FileHash -InputStream $stream -Algorithm $Algorithm
+    }
+}