Add possibility to customise clusterrole name

[ppawlowski]

Description

Increase configuration flexibility by adding a possibility to customise clusterrole name.
The reason for adding this feature is an attempt to install multiple FlowFuse apps on the same Kubernetes cluster. Since ClusterRole is a cluster-level object, the name must be unique.

Related Issue(s)

Checklist

• I have read the contribution guidelines
• Suitable unit/system level tests have been added and they pass
• Documentation has been updated
  • Upgrade instructions
  • Configuration details
  • Concepts
• Changes flowforge.yml?
  • Issue/PR raised on FlowFuse/helm to update ConfigMap Template
  • Issue/PR raised on FlowFuse/CloudProject to update values for Staging/Production

Labels

• Backport needed? -> add the backport label
• Includes a DB migration? -> add the area:migration label

[hardillb]

Check this PR where I had to revert similar for breaking upgrades #159

[ppawlowski]

Check this PR where I had to revert similar for breaking upgrades #159

Yep, an upgrade may fail on existing installations since AFAIK clusterrole name field is immutable. That is why I left a default value as it is but at the same time, if there is such a need, I allowed customising the name.
I have updated the PR description to explain the reason for the change.

[ppawlowski]

AFAIK clusterrole name field is immutable

I was not sure about it so I verified it.
The clusterrole name change introduced in #148 was not properly implemented. Indeed, changing clusterole name without recreating rolebinding object is not possible and ends up in:

Error: UPGRADE FAILED: an error occurred while rolling back the release. original upgrade error: cannot patch "create-pod" with kind RoleBinding: RoleBinding.rbac.authorization.k8s.io "create-pod" is invalid: roleRef: Invalid value: rbac.RoleRef{APIGroup:"rbac.authorization.k8s.io", Kind:"ClusterRole", Name:"newRoleName"}: cannot change roleRef: no ClusterRole with the name "create-pod" found

My change modifies rolebinding name as well so the problem does not exist during the upgrade process.