patman: add support for omitting bouncing addresses

Add support for reading a list of bouncing addresses from a in-tree file
(doc/bounces) and from the ~/.patman config file. These addresses are
stripped from the Cc list.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com <mailto:philipp.tomsich@theobroma-systems.com>>
diff --git a/doc/bounces b/doc/bounces
new file mode 100644
index 0000000..d1c5f0d
--- /dev/null
+++ b/doc/bounces
@@ -0,0 +1,3 @@
+# List of addresses picked up by patman/get_maintainer.pl that are known to
+# bounce. Addresses are listed one per line and need to match the author
+# information recorded in git.