Custom Object update mechanism

[chris-sanders]

Per the design in https://github.com/replicatedhq/troubleshoot/pull/662, design and implement a means to via the troubleshoot CLI:

• Check for installed Custom Objects for the defined CRD
• Check for upstream updates available for each object
• Upgrade objects that have a new version available

These tasks should be able to be completed via the CLI in two workflows.

1. An all in one workflow that will check and upgrade in a single command
2. An offline workflow which splits the "Check", "Download", and "Apply" stages into independent steps which can be run on two different machines; one machine with cluster access but no internet, the other machine with internet but no cluster access

Consideration should be given to allow Go projects which uses Troubleshoot as a vendored library to call these same steps directly w/o having to call the CLI.

The assumption is being made that working on both of the above workflows at once is easier than implementing the first and then trying to rework it to address workflow 2. If during design and implementation that is not believed to be the case we can split these two workflows into two issues.