feat: add support for poetry

New python dependencies are introduced by the memory mapping script.
Rather than add another `requirements.txt` utilise poetry. This is a
proper dependency management framework for Python. The two main upsides
of using poetry instead of the traditional requirements.txt are
maintainability and reproducibility.

Poetry provides a proper lock file for pinning dependencies, similar to
npm for JavaScript. This allows for separate environments (i.e. docs,
tools) to be created efficiently, and in a reproducible manner, wherever
the project is deployed.  Having dependencies pinned in this manner is a
boon as a security focused project. An additional upside is that we will
receive security updates for dependencies via GitHub's Dependabot.

Change-Id: I5a3c2003769b878a464c8feac0f789e5ecf8d56c
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
diff --git a/docs/getting_started/prerequisites.rst b/docs/getting_started/prerequisites.rst
index 5b49d2e..f30216a 100644
--- a/docs/getting_started/prerequisites.rst
+++ b/docs/getting_started/prerequisites.rst
@@ -98,6 +98,13 @@
    Git hooks and helper tools. Without these tools you will need to rely on the
    CI for feedback on commit message conformance.
 
+- Poetry >= 1.3.2
+
+  Required for managing Python dependencies, this will allow you to reliably
+  reproduce a Python environment to build documentation and run analysis tools.
+  Most importantly, it ensures your system environment will not be affected by
+  dependencies in the Python scripts.
+
 Package Installation (Linux)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
@@ -177,7 +184,7 @@
 
 --------------
 
-*Copyright (c) 2021-2022, Arm Limited. All rights reserved.*
+*Copyright (c) 2021-2023, Arm Limited. All rights reserved.*
 
 .. _Arm Developer website: https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/downloads
 .. _Gerrit Code Review: https://www.gerritcodereview.com/