Goal: OperatorHub/OLM users get a more intuitive UX around discovering and selecting Operator versions to install.

Problem statement: Today it's not possible to install an older version of an Operator unless the user exactly nows the CSV semantic version. This is not exposed however through any API. `packageserver` as of today only shows the latest version per channel.

Why is this important: There are many reasons why a user would want to choose not to install the latest version - whether it's lack of testing or known problems. It should be easy for a user to discovers what versions of an Operator OLM has in its catalogs and update graphs and expose this information in a consumable way to the user.

Acceptance Criteria:

• Users can choose from a list of "available versions" of an Operator based on the "selected channel" on the 'OperatorHub' page in the console.
• Users can see/examine Operator metadata (e.g. descriptions, version, capability level, links, etc) per selected channel/version to confirm the exact version they are going to install on the OperatorHub page.
• The selected channel/version info will be carried over from the 'OperatorHub' page to 'Install Operator' page in the console.
• Note that "installing an older version" means "no automatic update"; hence, when users select a non-latest Operator version, this implies the "Update" field would be changed to "Manual".
• Operator details sidebar data will update based on the selected channel. `createdAt` `containerImage` and `capability level`

Out of scope:

• provide a version selector for updatres in case of existing installed operators

Related info

UX designs: http://openshift.github.io/openshift-origin-design/designs/administrator/olm/select-install-operator-version/
linked OLM jira: https://issues.redhat.com/browse/OPRUN-1399
where you can see the downstream PR: https://github.com/openshift/operator-framework-olm/pull/437/files
specifically: https://github.com/awgreene/operator-framework-olm/blob/f430b2fdea8bedd177550c95ec[…]r/pkg/package-server/apis/operators/v1/packagemanifest_types.go i.e., you can get a list of available versions in PackageChannel stanza from the packagemanifest API
You can reach out to OLM lead Alex Greene for any question regarding this too, thanks