Update Sphinx theme re move to latest bootstrap #493

[phillxnet]

Fixes #493

This pull request's proposal

Address 'hamburger menu' inoperable - small screen header navigation issue by updating our custom theme and its bootstrap dependency.

In updating from a now very old bootstrap of v3.3.4/5, to v5.3.3, we have a number of changes required. Modify our custom 'rockstor' theme files accordingly.

Includes:

• Removal of redundant jslibs & css files.
• Update project metadata and syntax highlighting. The existing pygments_style in conf.py was not listed in comment reference added. Move to native as this is found in all themes.
• Re-enables highlight background override (in theme) for .highlight.
• Remove JQuery dependant _blank modifier for external links. This has been non-functional in production for some time now; removing, in the interests of minimising our doc html dependencies.
• Move Search element from maincontent to new/updated navbar configuration. Simplifies layout and saves space.
• Minor vertical tweak re logo positioning.
• Move all unspecified code-block:: elements to console. Unspecified code-block:: elements displayed suboptimally. Thus far we use console, text, bash, and yaml in order of frequency of use. All appear to format acceptably.
• Improve warnings format element: scrutiny.rst.

Checklist

• [x] With the proposed changes no Sphinx errors or warnings are generated.
• [x] I have added my name to the AUTHORS file, if required (descending alphabetical order).

[phillxnet]

Unrealated linkcheck failure:

Suspected temporary.

(       data_loss: line  207) timeout   https://subspace.kernel.org/etiquette.html - HTTPSConnectionPool(host='subspace.kernel.org', port=443): Read timed out. (read timeout=20)

[EDIT] A local (non GitHub host) run of Sphinx Link Check completed without error.

[phillxnet]

Testing

There no significant content changes in this PR, but we do have the referenced issue address thus:

Narrow view hamburger menu:

• non-active:

• active:

Wide view

[phillxnet]

PR product PRODUCTION published.