Add tool to create foxglove extensions

This tool lets users create new foxglove extensions by running the
equivalent of `npm init foxglove-extension@latest <patch>`.

A future patch will actually create a new extension using this tool.

Change-Id: Ifb3ca868fa72c30477a4943c3a6a805b06d0642d
Signed-off-by: Philipp Schrader <philipp.schrader@gmail.com>
diff --git a/tools/python/requirements.txt b/tools/python/requirements.txt
index ddbaef3..81d306d 100644
--- a/tools/python/requirements.txt
+++ b/tools/python/requirements.txt
@@ -15,6 +15,7 @@
 validators
 yapf
 sympy
+pyyaml
 
 # TODO(phil): Migrate to absl-py. These are abandoned as far as I can tell.
 python-gflags