The default VSX registry should be openvsx.org

[l0rd]

Is your enhancement related to a problem? Please describe

We are about to embed an OpenVSX registry in Che plugin registry but that hasn't be tested thoroughly yet and we still want to use openvsx.org as the default registry to retrieve VS Code extensions.

Describe the solution you'd like

When installing Che (via OLM or yaml manifests), the default CheCluster should have pluginRegistry.openVSXURL set to https://openvsx.org.

When updating Che v7.51 or earlier, if pluginRegistry.openVSXURL is NOT set then we should set it to https://openvsx.org.

When updating Che v7.52 or later, if pluginRegistry.openVSXURL is NOT set then we should not modify it.

Additional context

We introduced the pluginRegistry.openVSXURL with this PR but that field is empty by default (meaning that the embedded registry will be used).

OpenVSX is greedy in terms of memory requirements.

[svor]

When updating Che v7.52 or later, if pluginRegistry.openVSXURL is NOT set then we should not modify it.

@l0rd @tolusha it means that updated Che v7.53 will have empty value of openVSXURL and will use the embedded registry. It changes the previous state that was in v7.52 were we use online registry.

maybe we should:
When updating Che v7.52 or earlier, if pluginRegistry.openVSXURL is NOT set then we should set it to https://openvsx.org/.
When update Che v7.53 or later, if pluginRegistry.openVSXURL is NOT set then we should not modify it.

[l0rd]

@svor I think you are right: in v7.52 and earlier version pluginRegistry.openVSXURL is empty by default (but openvsx.org is supposed to be used). It's only from v7.53 that pluginRegistry.openVSXURL is set by default to https://openvsx.org. My bad, I got confused with the release numbers.