Upgrade gb-asm-tutorial to use mdbook 0.5

[mtthgn]

This PR makes a number of changes, all necessary to address breaking changes introduced in mdBook 0.5:

1. It makes the preproc and i18n-helpers crates now depend on mdbook-preprocessor. As part of 0.5 the mdbook crate was broken down into components.
   • The PreProcessor trait slightly changed. The supports_render function now returns a Result<bool> instead of merely a bool: Add optional field for preprocessors rust-lang/mdBook#2797
   • get_preprocessor was removed, so I had to use get instead: Remove toml as a public dependency rust-lang/mdBook#2773
2. It makes the renderer crate now depend on mdbook-renderer and mdbook-html. This one is mostly just updating use names.
3. It switches the {{#previous}} and {{#next}} handlebars statements to the new syntax: Replace navigation helpers with objects rust-lang/mdBook#2794
4. It updates github workflows to install the appropriate versions of mdbook related crates.

As part of this update, the theme/index.hbs had to be updated to work with some syntax changes made for mdbook 0.5. The style looked pretty off in my browser (no header nav, sidebar doesn't adjust width, content alignment at certain breakpoints is off), so I would appreciate someone double checking on this front. I'm not sure if this is akin to how pandocs need to be served differently than mdbook serve, or if something actually broke. Looking at the currently deployed docs, the reason for a custom theme is not immediately apparent to me.

Edit by @avivace:
Note: The PR is still in draft pending restoration of the custom theme's localization-related customizations, which appear to have broken as part of the theme/index.hbs update.

Closes #134

[mtthgn]

@avivace the additional-css config for ouput.html.print doesn't seem to be an option as of mdbook 0.5. I added the print css to the output.html section, but printing looked very off. I might need some assistance understanding what the goals were for the print css, and from there we can figure out how to achieve that on the current version of mdbook

[mtthgn]

I read a bit more through #193, and I think it'd be helpful if @OnStarPrograms / @avivace could further confirm the intention the CSS in that PR.

Is the goal to display the contents of all the "answers" throughout the tutorial, while also hiding the "Answer (click me)" text? If so, the current implementation only does that for <detail> tags that were opened before clicking the print button. You can confirm this on the currently deployed site. Is that the desired behavior, or is the intention to have all of the answers opened and present in the printed version?

[avivace]

@mtthgn On the print version everything should be 'expanded', I believe that was the idea of that PR (and the correct rationale, imo). So displaying all questions and all answers

[mtthgn]

@avivace thanks for the clarification! I've simplified the CSS and added a bit of javascript to ensure that always occurs. Unfortunately there's no way to guarantee they're in an open state for printing without javascript at the moment.