Add mechanism for users to specify accessible namespaces

[Nokel81]

The namespaces which are accessible to them. This is generally useful for when the user doesn't have permission to list the namespaces.

• Add new component "EditableList" which provides a simple way to
  display a list of items that can be added too.

• Add the ClusterAccessibleNamespaces to the GeneralClusterSettings

Signed-off-by: Sebastian Malton smalton@mirantis.com

closes #486

This is a draft PR because it should be targeting master but vue_react_migration hasn't been merged to master yet.

[Nokel81]

@nevalla changed base to master

[aleksfront]

@Nokel81 Do you have real-world example of a test case for a user without namespace listing rights? Currently I am unable to create such a user. Tested with

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  # "namespace" omitted since ClusterRoles are not namespaced
  name: ns-getter
rules:
- apiGroups: [""]
  resources: ["namespaces"]
  verbs: ["create"]

and

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: read-namespaces-global
subjects:
- kind: User
  name: user1 # Name is case sensitive
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: ClusterRole
  name: ns-getter
  apiGroup: rbac.authorization.k8s.io

With this settings the results are actually really strange: namespaces wouldn't listed no matter what's included in the Accessible Namespaces.

[Nokel81]

@aleksfront Sorry I do not have a testing case, I am going off of what what the initial issue said

[nevalla]

Generally looking good and I was able to see those namespaces that I was set in cluster settings. Related to configuring namespaces, can we have some hint that editable list that it requires pressing enter to add an item?

Also, probably out of scope of this PR, but after configuring allowed namespaces we should somehow send a signal to the dashboard to update namespaces list.

[Nokel81]

@nevalla Good idea, when I close this I will make a follow up ticket.

@aleksfront Given Lauri's review, can you accept this PR?

[aleksfront]

LGTM with minor i18n comments!