Publish separate images for precise-code-intel processes.

Created by: efritz

There is some deployment friction having one "precise-code-intel server": the user needs to set three environment variables to have a separate image for the api server, bundle manager, and worker.

This change publishes distinct images for the three precise code intel entrypoints so that the nine envvars can be dropped from deployment contexts entirely.

This blocks further updates to https://github.com/sourcegraph/deploy-sourcegraph/pull/574.