Preparing for submissions

[zvr]

The files in this repo are used to create three different editions of the Specification:

1. the one presented in HTML
2. a PDF, to be submitted to OMG
3. a PDF, to be submitted to ISO

Unfortunately, the content is not exactly the same in all of them.

This PR:

• Moves files around to facilitate preparation of the 3 editions
• Updates mkdocs config to use new paths (for the first one)

Note:
There will be a fourth edition, a PDF version for SPDX website, but this content will very closely match the HTML one (1, above) and in any case is not ready right now.

[goneall]

Changes look reasonable to me with the caveat that I don't have much expertise in the mkdocs tooling.

[bact]

There are currently two warnings during PR validation:

WARNING - Doc file 'front/index.md' contains a link './licenses/Community-Spec-1.0.md', but the target 'front/licenses/Community-Spec-1.0.md' is not found among documentation files.

WARNING - Doc file 'front/index.md' contains a link './licenses/CC-BY-3.0.md', but the target 'front/licenses/CC-BY-3.0.md' is not found among documentation files.

[bact]

Links in Lines 9 and 13 may need to update:

• ./licenses/Community-Spec-1.0.md -> ../licenses/Community-Spec-1.0.md

• ./licenses/CC-BY-3.0.md -> ../licenses/CC-BY-3.0.md

[zvr]

It's unfortunate that mkdocs and LaTeX treat relative filenames differently...
On the other hand, we're fortunate that this is only on the index file, which is different in LaTeX editions anyway, so no harm done.

[editing this comment:]
ah, it's not file inclusion, it's link reference. Ignore the previous.