adds revises downloads page, adds package page, updates package data

[stockholmux]

Description

This revises. the downloads page extensively.

1. Updates to the package manager information at each version
2. Adds a page with grid of versions and package managers.
3. Moves the artifact_source from each release files to a central data file since it never changes

Screenshots:

Package Manager page:

New section on downloads and each release:

Issues Resolved

#131

Check List

• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the BSD-3-Clause License.

[madolson]

Do we really want to be maintaining that dot array? I suppose either:

1. Can we just indicate the minor versions supported. I think that is what is the most useful for what end users support and dramatically reduces the frequency of updates.
2. I wonder if we should just merge it into the Package manager table. Add in the notes, "known support for 8.0".

[stockholmux]

@madolson I do think it's necessary: the gap it fills is that our release pages show the places you can get a given version; I think that's reasonably required information. However, because some package managers lag considerably (e.g. Ubuntu currently only has 7.2.5), looking only at a single version could lead someone to believe that Valkey isn't available in a given package manager.

Originally, I did consider having this information only appear on the release page with a row for each distro and the last version supported. However, this got very complicated to present multiple version lines. The dot array, IMHO, is the easiest way to represent the entire landscape.

Also, the dot table is actually just a representation of the same data in the package manager table, so it's no extra maintenance is needed, new package managers automatically appear on this table as soon as they are added to any version.