add helper function for pester

src/Helper/Get-ModuleBase.ps1

@@ -0,0 +1,29 @@
+function Get-ModuleBase {
+    <#
+    .SYNOPSIS
+        Returns the base path of the current module.
+
+    .DESCRIPTION
+        This is just a wrapper for enabling pester tests.
+
+
+    .OUTPUTS
+        Returns the base path as string
+
+    .NOTES
+        File Name   : Get-ModuleBase.ps1
+        Author      : Marco Blessing - marco.blessing@googlemail.com
+        Requires    :
+
+    .LINK
+        https://github.com/OCram85/PSCredentialStore
+#>
+    [CmdletBinding()]
+    [OutputType()]
+    param()
+    begin {}
+    process {
+        return $MyInvocation.MyCommand.Module.ModuleBase
+    }
+    end {}
+}