Create navi.plugin.psm1

Moves the file to the base folder, removed cmdlets handlers and related options. Still needs modifications.

shell/navi.plugin.psm1

@@ -0,0 +1,30 @@
+
+### Initial code from @lurebat (https://github.com/lurebat/)
+### See #570 (https://github.com/denisidoro/navi/issues/570) for its original contribution
+function Invoke-NaviWidget {
+    $ast = $tokens = $errors = $cursor = $null
+    [Microsoft.PowerShell.PSConsoleReadLine]::GetBufferState([ref] $ast, [ref] $tokens, [ref] $errors, [ref] $cursor)
+
+    $line = $ast.ToString().Trim()
+    $output = $null
+
+    if ([String]::IsNullOrEmpty($line)) {
+        $output = navi --print
+    }
+    else {
+        $best_match = (navi --print --best-match --query $line | Out-String).Trim()
+        if ([String]::IsNullOrEmpty($best_match)) {
+            $output = (navi --print --query "$line" | Out-String).Trim()
+        }
+        else {
+            $output = $best_match
+        }
+    }
+
+    [Microsoft.PowerShell.PSConsoleReadLine]::RevertLine()
+
+    ### Handling the case when the user escapes without selecting any entry
+    if (-Not([String]::IsNullOrEmpty($output))) {
+        [Microsoft.PowerShell.PSConsoleReadLine]::Insert([String]$output)
+    }
+}