Realm Password policies

[tomrutsaert]

Added Support for password policies.
It checks if the password policy provider is installed.
I did not change or wrap the syntax of the realm password policy string the keycloak API uses.

[tomrutsaert]

Some checks were not successful
1 failing and 1 successful checks:
ci/circleci: test-password — Your tests failed on CircleCI

--> These test seem to be flaky, they fail often but not always, the failure has nothing to with my change.

[mrparkers]

They are flaky, I can merge this regardless. Thanks for the contribution!

[timbmg]

could your provide an example for this?

[tomrutsaert]

resource "keycloak_realm" "test" {
  realm               = "test"
  enabled              = true
  password_policy = "upperCase(1) and length(8) and forceExpiredPasswordChange(365) and notUsername"
}

The provider uses the same password policy string that keycloak uses itself.

You should always find at least on example for each feature in the example files:
https://github.com/mrparkers/terraform-provider-keycloak/tree/master/example

I should add this to the documentation (I do tend to forget this)