Allow user to specify curated packageBundle version during cluster install

**What would you like to be added**:
Currently versioning of curated package bundle is not allowed because of by default latest curated package bundle gets activated on the cluster. I would like to have a key in the cluster spec using which one can specify a `packagebundle` version.

**Why is this needed**:
It allows controlled release of packages in production. If QA team has tested EKSA cluster lifecycle against a specific `packageBundle` version then production should get the same version as opposed to latest available at the time of cluster creation in Production.

No files or tests are named in the issue. Trace the cluster spec and curated package bundle activation path during cluster installation, then identify where a requested packageBundle version would be parsed and applied. Done means the version can be specified in the cluster spec, is used during installation instead of the latest bundle, and is covered by relevant tests.

Written by the indexing model from the issue text.