[Detect] Fail fast if buildpack.toml mixins are not satisfied by stack

[natalieparellano]

By reading application buildpacks' buildpack.toml, the lifecycle can know what mixins are being statically requested.

The lifecycle can know what mixins are pre-installed on the stack by reading analyzed.toml.

Therefore, if all statically requested mixins are NOT satisfied by the stack, the lifecycle should fail.

[srisatya12]

I want to work on this issue.

[natalieparellano]

@srisatya1197 that's awesome! This issue is currently blocked on the unresolved question here: #573

How should analyzed.toml be changed to include run-image information (mixins)

but we'll do our best to get it un-blocked as soon as possible.

Given that this issue is part of a larger epic that is currently taking shape, and thus requires a higher level of coordination, it would be great if you could join the discussion in our Slack #implementation channel.

[natalieparellano]

As per discussion here: buildpacks/spec#197 (comment) this belongs in analyze, not detect.

[natalieparellano]

Moving this back to detect, as each buildpack.toml won't be available to the analyzer.

[natalieparellano]

Breaking this into two issues as 0.12.0 won't have knowledge of stackpacks.

[natalieparellano]

Removing this from 0.12.0 milestone for the same reason as #573 (comment)