Support seamless/automated SDP upgrades on Openshift

[razvan]

Description

Currently each new SDP release that is published to the RH catalogs seems to override the older versions.

Investigate the possibility to:

• install older versions of an operator from the RH catalog
• upgrade to a newer version from the RH catalog

Acceptance criteria

• [x] There is way to test that an operator can be upgraded by updating it's catalog with a new version.
• [x] The build-manifests.py is updated with support for upgrade paths.

Implementation details

The build-manifests.py script now accepts a couple of arguments related to operator publishing and upgrades:

• --channel : the channel to publish the operator to. By default, for 0.0.0-dev versions, the alpha channel is used. For all others the <year>.<month> channel is parsed from the --release argument.
• --skips : the versions OLM should skip when upgrading the operator. Default: none
• --replaces : the older version OLM should replace. Default: none.

Findings

ClusterServiceDefinition (CSV) objects have a replaces field that points to the previous version of the CSV that the current is replacing. The upgrade workflow is described here.

Patch releases should probably be skipped by adding the skips property to the current CSV.

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From RedHat provided catalogs:

As catalogs are updated, the latest versions of Operators change, and older versions may be removed or altered

[sbernauer]

Thanks for working on this @razvan! Can this issue be moved to Done? I added the demo-needed label, as I would be interested to see how OS users can update our stuff (via UI?), but if it's a too big effort to demo this please feel free to remove the label again