Add repo spec hash to its name
This helps to ensure that a given generation of SUR reconciles the desired repo version.
This will help to prevent race conditions, as we've done in sylva-projects/sylva-core!2751 (merged)
But suspending/resuming sylvaUnitsHelmRelease is hard to achieve in an operator, it seems more relevant to add suffixes to resources names to ensure that HelmRelease will reconcile with the desired source version.
As SUR will generate multiple gitRepositories, we need to prune them when they are not referred any more.
This is done in a generic way in pruneManagedResources method, as we'll need to do the same for Secrets and ConfigMaps with generated names.
We also add tests where we change the version and ensure that old repository is deleted.
Relates to: #26 (closed)