BB Gitlab should default to deny users ability to create group

We should configure the gitlab that bigbang installs to default to deny users the ability to create group to better match the desired state of PB.

# relevant gitlab values
global:
  appConfig:
    defaultCanCreateGroup: false

/cc @matthew.kaiser @kevin.wilder

added gitlab label

marked this issue as a duplicate of #456 (closed)

closed

marked this issue as related to #456 (closed)

Adding @kelly.yushko as co-assignee.

assigned to @kelly.yushko