Fixes errors encountered when handling SVG graphics, unicode characters,
and deeply nested lists (i.e. in the change log) with the `latexpdf`
docs build. Adds `sphinxcontrib-svg2pdfconverter` to allow embedding SVG
images into PDF files; changes the LaTeX engine to XeLaTex to provide
wider support for unicode characters (see [1] for more details); and
increases the maximum list depth.

[1] https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-latex_engine



Change-Id: I2ee265d301f6822bae7aa6dfa3a8bfcf070076d3
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>

Make the symbol table produced by the memory mapping script more
readable. Add a generic interface for interacting with ELF binaries.
This interface enables us to get symbols that provide some insights into
TF-A's memory usage.

Change-Id: I6646f817a1d38d6184b837b78039b7465a533c5c
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>

Click is used in parts of the CI scripts (see run_config/fvp-linux.tc
for instance), add it back as part of a new dependency group. Future
dependencies that are required only in CI should be added to the
``ci`` dependency group.

Change-Id: I5da7fea703495dd4006d86334626f126a850bb10
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>

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>