[New Resource] Add support for multiple group for local user

[anthonyroussel]

Description

The ovh_me_identity_user resource currently accepts a single group attribute, mapping a local user to exactly one group.

The ability to assign a local user to multiple identity groups has since been implemented on the API side recently.

The goal of this ticket is to implement this functionnality in the OVH Terraform Provider.

Requested Resource(s) and/or Data Source(s)

• ovh_me_identity_user_group_membership

Potential Terraform Configuration

resource "ovh_me_identity_user" "john" {
  login       = "john.doe"
  email       = "john.doe@ovh.com"
  password    = "john123"
  description = "John Doe"
}

resource "ovh_me_identity_user_group_membership" "john" {
  login  = ovh_me_identity_user.john.login
  groups = [
    ovh_me_identity_group.project_a.name,
    ovh_me_identity_group.project_b.name,
  ]
}