implement deploy logs view for helm managed mode

[stefanrepl]

What this PR does / why we need it:

This PR implements deploy logs API response for KOTS when running in helm managed mode

Which issue(s) this PR fixes:

Fixes # https://app.shortcut.com/replicated/story/54248/404-returned-when-trying-to-view-deploy-logs

Special notes for your reviewer:

Steps to reproduce

Does this PR introduce a user-facing change?

     Show deploy logs of helm charts when running in [Helm managed mode (Alpha)](/vendor/helm-install).

Does this PR require documentation?

Loom: https://www.loom.com/share/9ea4867e71fc4087b572d9f7d53b7c20

[divolgin]

Presumably this is received in the watch loop with secret info. Is there a revision number? The output should match the correct revision, but this will be shown for all revisions of the app. The API handler receives sequence number. It should be used the retrieve matching output.