Improve navigation bar and more

[salim-b]

• Improve / simplify navigation bar styling and remove params.logo_width from config.toml (i.e. revert https://github.com/themefisher/airspace-hugo/commit/563b41cfc4c31edfd5908f50e2a625b7c39eca89) since it doesn't play nicely with CSS-based styling

• Allow setting SCSS variables in config.toml and rename variables to have semantic prefixes

• Clean up / tidy various SCSS and HTML files and add trailing newlines to all text files to make them POSIX-compliant

• Fix Google Maps JS snippet inclusion and avert use of partialCached for footer.html since it breaks conditional logic (because with partialCached the partial is only executed once per site)

• Replace absURL -> relURL and .Permalink -> .RelPermalink in all remaining places to make the theme more portable, cf. https://github.com/themefisher/airspace-hugo/pull/118

• Add Italian 404 redirect rule for Netlify

[somratpro]

Hello @salim-b

Thanks for your contribution, You have changed so much stuff, actually, we don't need to change those things, and we don't want to. You can contribute to updating a specific thing. I am closing this PR for now, thank you.

[salim-b]

Hi @somratpro

Ok, I understand that this PR was too extensive to be soberly reviewable... 🙉 I'll split things up into smaller PRs, starting with https://github.com/themefisher/airspace-hugo/pull/130. Hope that's fine.