Unify metadata files back into one

[Leonidas-from-XIV]

Undoes some of the changes in #186 be joining the stable metadata into the same file.

Closes #198.

[ElectreAAS]

I've taken a look, and while I haven't found any gross mistakes, I gotta say I just don't know enough about the project to take responsibility in approving formally

[Leonidas-from-XIV]

Yes, that's very fair. In an attempt to fill you in a bit: the metadata.json files contain a list of so called "Bundles", that's basically a nightly build or a stable build. These get created by the Github action workflows and committed to the repo every night. This data then gets used by the server to know where to redirect the user when they request the "latest" build (e.g. it checks that there is a build for the requested platform, figures out when it was and decodes this into a the proper URL to forward to).

When I added stable builds I thought it would be necessary to have a different Bundle format for stable builds. But as it turns out it was totally enough to just add an optional tag field (that would contain the release tag name) and... that's it. All the other fields can still be populated and might be useful to some degree so when I talked with @Sudha247 she said (paraphrased) "oh, but why are they then separate files". And then I realized that there is no reason why they would need to be separate files actually and they can be combined back into metadata.json which makes a few things a bit easier (e.g. we can have a command line argument to specify the metadata instead of hardcoding them, we don't need to remember to add both files everywhere necessary etc.).

[Sudha247]

LGTM!

I have some follow-up questions:

• Do I understand correctly that this is an internal change on the file representations and doesn't affect external (user-facing) endpoints such as https://get.dune.build/install?
• Are there plans to display the stable binaries in the nightly site, with instructions on how to install them?

[Leonidas-from-XIV]

@Sudha247, good questions! To answer them one by one

• Yes. The outside view should not be affected by this change at all. It's really just basically acknowledging that the format for stable and nightly is the same and avoids a @ operation on lists and makes the UI a bit less wonky. As such only the server (which reads the metadate) and the workflows (which edit the metadata) are affected.
• Yes, possibly. It's definitely in the realm of possibility, generally the website needs to be somewhat reworked to not only present nightlies but also stable releases. Extend binary installer to support the new /stable endpoint #202 does the first step of providing a download link for the stable release but in the long term listing the releases that have builds would also make sense. I've opened List stable releases on website #204 to track this.