docs(memory management): rme integration

General documentation about memory sharing feature,
and added details about RME integration.

Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: I2758ccb942a09c496f1b15d91683d1a8284b2128
diff --git a/docs/glossary.rst b/docs/glossary.rst
index 078b0f6..a87df89 100644
--- a/docs/glossary.rst
+++ b/docs/glossary.rst
@@ -98,6 +98,9 @@
    PA
       Physical Address
 
+   PAS
+      Physical Address Space
+
    PE
       Processing Element
 
@@ -118,6 +121,9 @@
       extension for the Armv8.2 architecture and later. An optional extension to
       the base Armv8 architecture.
 
+   RME
+      Realm Manage Extension
+
    ROP
       Return-Oriented Programming