Streamlined pwsz loading from Linux shells

Get-Path updated to support @ notation.
MyConfig class updated to resolve Paths before testing.
MyScript class will look recursivley - this might need to change again.
config.files.json updated to support shell-loading-snippets
shell-loading-snippets added, with single line of code to inject into
startup shell scripts (.zshrc, .bashrc, .shrc)

base/Get-Path.ps1

@@ -1,6 +1,9 @@
 [CmdletBinding()]param([string]$Path)
 
 try {
+    if( $Path[0] -eq '@' ) {
+        $Path = Join-Path $MyPSScriptRoot $Path.Substring(1)
+    }
     get-item $Path -Force -ErrorAction Stop | 
         Select-Object -ExpandProperty FullName
 } catch {