docs(rme): add build and run instructions for FEAT_RME

This patch adds instructions on how to build and run TF-A
with FEAT_RME enabled. The patch also adds code owners for
FEAT_RME.

Signed-off-by: Zelalem Aweke <zelalem.aweke@arm.com>
Change-Id: Id16dc52cb76b1ea56ac5c3fc38cb0794a62ac2a1
diff --git a/docs/components/index.rst b/docs/components/index.rst
index 2409f96..f349d8d 100644
--- a/docs/components/index.rst
+++ b/docs/components/index.rst
@@ -22,3 +22,4 @@
    ffa-manifest-binding
    xlat-tables-lib-v2-design
    cot-binding
+   realm-management-extension