Meta Title, Nav Title, Heading, breadcrumb - understand and improve

[darrentayloruk]

Breadcrumbs have been added but the final breadcrumb for current page uses the page.title value

In this setup this is pulling out the meta title

The nav is currently built using the headings from the .md files so it's not consistent and we want to add more detail in the meta title for better searchability

See what we can do to make this better.
Try to understand more of this template features
Set out a guide in the readme with finding.

[darrentayloruk]

Documenting update here

Worked out a way to extract the navigation title used for the current page from the TocTree, so breadcrumbs will be consistent and we can add more into th meta title

Navigation titles are pulled from the title (h1) of the .md documents, but can be overidden from within the index.rst files where the ToC is defined see https://www.sphinx-doc.org/en/1.5/markup/toctree.html