Add the gifn-apply test tool

Add a tool that checks out the repositories mentioned in
a git-if-needed patch series, runs gif-it-needed, and performs
some checks on its operation. This tool will eventually be used in
a Zuul test job for this repository.

Change-Id: Id02fb7c21f5ab34d9639bf845fcc3961d929b13b
diff --git a/tools/git-if-needed/.editorconfig b/tools/git-if-needed/.editorconfig
index 26fbee5..b9f4c15 100644
--- a/tools/git-if-needed/.editorconfig
+++ b/tools/git-if-needed/.editorconfig
@@ -1,4 +1,7 @@
 # https://editorconfig.org/
+#
+# SPDX-FileCopyrightText: StorPool <support@storpool.com>
+# SPDX-License-Identifier: BSD-2-Clause
 
 root = true
 
@@ -20,6 +23,14 @@
 indent_style = tab
 tab_size = 8
 
+[*.py]
+indent_style = space
+indent_size = 4
+
+[*.toml]
+indent_style = space
+indent_size = 2
+
 [sh/git-if-needed]
 indent_style = tab
 tab_size = 8