[minor] Allow installPlanApproval and startingCSV to be set on subscriptions

[whitfiea]

Resolves ibm-mas/ansible-devops#2149

Updates the olm.py to allow the applySubscription function to be passed in an optional installPlanApproval and startingCSV value. This is primarily used in the case where were the latest subscription version has an issue and so the solution is to install a previous one and stop OLM from automatically updating. The case that caused this to be added was the grafana-operator update.

The logic in the function is as follows:

• installPlanApproval and startingCSV are optional, not providing them is what happens without this fix which is automatic approval.
• installPlanApproval set to manual requires startingCSV to be set.
• if we have an installplan created with the clusterservicename containing the startingCSV then we approve that install as that will be the one required.
• any installplan that does not contain the startingCSV will not be approved automatically.
• if the subscription status is UpgradePending and installPlanApproval is manual then we check the installplan we want is complete and return.

Tested using the grafana-operator and with PR in ansible-devops both locally and in fvt-personal:

Unit tests added/updated.