Add help.deps scripts to all first party plugins (to demonstrate the best practice)

[sschuberth]

Is your feature request related to a problem? Please describe

My problem is that even with #757, installing dependencies of a plugin is still too hard, mostly because plugin authors do not add a help.deps script.

Describe the proposed solution

The first party plugins should lead by example and provide help.deps scripts that output dependencies for a TBD set of "basic" platform, like Ubuntu, Fedora, Alpine.

Once that's done, the "Getting Started" guide should be extended to show how the output of help.deps can be used to install plugin dependencies (semi-)automatically.

Describe similar asdf features and why they are not sufficient

Determining and installing plugin dependencies manually is cumbersome and defeats the purpose of a tool like asdf, which is to automate tool setup.

Describe other workarounds you've considered

As suggested here, the presence of a working help.deps script should and could actually be enforced.

[jthegedus]

Just to clarify, help.deps is only useful after the plugin has been installed and before the tool is installed by the plugin.

As an example for those who want to help with this effort, https://github.com/jthegedus/asdf-v is an example of mine which uses this API.

@sschuberth I believe Issues for adding help.deps to plugins should be in the repo of the plugins.

Other than making help.deps a hard requirement, what would you consider enough to close this Issue, just a docs update outlining help.deps and note about reading the plugin README?

[sschuberth]

what would you consider enough to close this Issue, just a docs update outlining help.deps and note about reading the plugin README?

I would consider that to be a proper solution to the problem, but it's certainly better than nothing.