Add `security_group_ids` support to `yandex_gitlab_instance`

[tcaty]

Problem description

Currently it's not possible to assign security groups to GitLab instance via terraform. We have to do it manually via Yandex Cloud ui. It would be great to manage all GitLab settings via terraform.

Desired Usage Example

resource "yandex_gitlab_instance" "this" {
  ...
  security_group_ids = [
    yandex_vpc_security_group.gitlab_sg_a.id,
    yandex_vpc_security_group.gitlab_sg_b.id,
  ]
  ...
}