Expand deployments document structure

To cope with the growing number of deployments, the documentation
structure for deployments has been expanded to include sub-pages
for the different types of deployment. This commit includes
fuller descriptions of SP deployments.

Signed-off-by: Julian Hall <julian.hall@arm.com>
Change-Id: Id383cdb67f9e1e3a515e81673cc84077f77b5562
diff --git a/docs/developer/index.rst b/docs/developer/index.rst
index 33a03cc..5fe886f 100644
--- a/docs/developer/index.rst
+++ b/docs/developer/index.rst
@@ -10,7 +10,7 @@
     portability-model
     service-access-protocols
     service-locator
-    deployments
+    deployments/index
     service-descriptions/index
     software-requirements
     build-instructions
@@ -21,6 +21,6 @@
 
 --------------
 
-*Copyright (c) 2020-2021, Arm Limited and Contributors. All rights reserved.*
+*Copyright (c) 2020-2022, Arm Limited and Contributors. All rights reserved.*
 
 SPDX-License-Identifier: BSD-3-Clause