[epic] Support direct bundle installation

[ncdc]

After #596 goes in, we can implement support for installing a bundle from a URL instead of resolving it from a catalog. To do this, we'll have a very strict set of guardrails:

1. The bundle must be a registry+v1 bundle
2. We will do minimal or no constraint/dependency checking - a direct bundle installation is considered "satisfied"

[ncdc]

FYI @varshaprasad96

[acornett21]

With the switch happening from rukpak to kapp, it would be great if direct installs could also support Helm. The use case would be that if a helm chart exists in a helm repo, the kapp controller would be able to install it directly. The reason why this use case is important, is that it is unlikely that a helm chart maintainer would build a catalog to wrap their chart, but instead they publish it to a chart repo.

[grokspawn]

A candidate brief started (but not reviewable) here

[joelanford]

I implemented a proof of concept as part of #1418. We should revisit that PR when we have time to pick this issue up.

[grokspawn]

This requires us to determine a way to feature-gate API changes before we could work it.