Documentation: Add 4.10/4.11 release notes

For 4.11 that's obviously just the release notes template.

Change-Id: I44c15bcaedf1367d745c533cc0a4acebdd2f812e
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34469
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

Documentation/releases/coreboot-4.11-relnotes.md

@@ -0,0 +1,17 @@
+Upcoming release - coreboot 4.11
+================================
+
+The 4.11 release is planned for October 2019
+
+Update this document with changes that should be in the release
+notes.
+* Please use Markdown.
+* See the [4.9](coreboot-4.9-relnotes.md) and [4.10](coreboot-4.10-relnotes.md)
+  release notes for the general format.
+* The chip and board additions and removals will be updated right
+  before the release, so those do not need to be added.
+
+Significant changes
+-------------------
+
+### Add significant changes here