west: Add untracked files and folders to west status output

Add untracked files and folder to west status output.
This helps to keep the west checkout clean by alerting the user
of folders that are no longer tracked by west.
This is useful for detecting when a module has been removed, or moved.
and is no longer updated by west update.

Add the ability to ignore folders and files through a comma separated
list in the west config file.
Example:
west config status.ignore .vscode/,optional/

Fixes: zephyrproject-rtos#622

Signed-off-by: Joakim Andersson <joakim.andersson@nordicsemi.no>

src/west/app/project.py

@@ -844,6 +844,53 @@ def do_run(self, args, user_args):
                 failed.append(project)
         self._handle_failed(args, failed)
 
+        # List projects not tracked by manifest.
+        projects = [project.abspath for project in self._cloned_projects(args, only_active=True)]
+        topdir = Path(self.topdir)
+        untracked = []
+
+        self.do_find_untracked(topdir, projects, untracked)
+
+        ignored_config = self.config.get('status.ignore')
+        ignored = ignored_config.split(',') if ignored_config else []
+        # Ignore .west folder in untracked projects
+        ignored.append('.west/')
+        for ignore in ignored:
+            try:
+                untracked.remove(ignore)
+            except:
+                pass
+
+        if len(untracked) > 0:
+            self.banner('untracked:')
+            for project in untracked:
+                self.inf(textwrap.indent(f'{project}', ' ' * 4))
+
+    def is_manifest_subfolder(self, path, projects):
+        for project_path in projects:
+            try:
+                if Path(project_path).relative_to(Path(path)):
+                    return True
+            except ValueError:
+                pass
+        return False
+
+    def do_find_untracked(self, path, projects, untracked):
+        obj = os.scandir(path)
+
+        for entry in obj:
+            if entry.is_dir():
+                if entry.path in projects:
+                    continue
+                if self.is_manifest_subfolder(entry.path, projects):
+                    self.do_find_untracked(entry, projects, untracked)
+                else:
+                    untracked.append(os.path.relpath(entry.path, Path(self.topdir)) + '/')
+            if entry.is_file():
+                untracked.append(os.path.relpath(entry.path, Path(self.topdir)))
+
+        obj.close()
+
 class Update(_ProjectCommand):
 
     def __init__(self):