.gitignore: Ignore all dot files and folders except the standard ones

Improve the gitignore to handle dot files and dot folders that are
created by most of development tools, such as IDEs.

This patch allows OPTEE-OS developers to store their specific tool
configurations under dot files or folders and not be bothered by the output
of the git status command.

Signed-off-by: Clément Le Goffic <[email protected]>
Reviewed-by: Jerome Forissier <[email protected]>
Acked-by: Jens Wiklander <[email protected]>
Reviewed-by: Etienne Carriere <[email protected]>

.gitignore

@@ -1,8 +1,14 @@
-/.cproject
 /compile_commands.json
 /cscope.*
 /tags
 /TAGS
 /out
 /.project
-*.swp
+# Ignore all dot files and folder
+.*
+# But not those
+!.clang-format
+!.checkpatch.conf
+!.gitattributes
+!.gitignore
+!.github