Remove the override to kolla_base_distro & version

When running the kayobe-automation CI on a Zed/Antelope cloud running
Ubuntu host images, these variable overrides cause the kolla tags to
template incorrectly. For example, a Jammy host gets
``kolla_base_distro_and_version = rocky-jammy``.

Given we will not be performing any host OS migrations on Zed (or
Antelope), we can remove these overrides and use the default values
based on ``os_distribution``.

Bug explanation:

These variables end up with the following values, meaning the CI picks
up rocky but keeps jammy.

```
kolla_base_distro: '{{ ansible_facts.distribution | lower }}'
kolla_base_distro_and_version: '{{ kolla_base_distro }}-{{ kolla_base_distro_version}}'
kolla_base_distro_version: jammy
```

This is because the variables are first templated under the Kayobe
group_vars based on os_distribution, so the version maps to jammy.
``kayobe/ansible/inventory/group/vars/all/kolla``

```
kolla_base_distro: "{{ os_distribution }}"

kolla_base_distro_version_default_map: {
  "centos": "stream9",
  "debian": "bullseye",
  "rocky": "9",
  "ubuntu": "jammy",
}

kolla_base_distro_version: "{{ kolla_base_distro_version_default_map[kolla_base_distro] }}"
```

Then, the base distro and the final variable are overwritten in kolla
globals kayobe-config/etc/kayobe/kolla/globals.yml

```
kolla_base_distro: "{% raw %}{{ ansible_facts.distribution | lower }}{% endraw %}"

kolla_base_distro_and_version: "{% raw %}{{ kolla_base_distro }}-{{ kolla_base_distro_version }}{% endraw %}"
```

Author: MoteHue

etc/kayobe/kolla/globals.yml

@@ -6,13 +6,6 @@
 # non-overcloud hosts
 enable_docker_repo: "{% raw %}{{ 'overcloud' not in group_names }}{% endraw %}"
 
-# kolla_base_distro must be set here to be resolvable on a per-host basis
-# This is necessary for os migrations where mixed clouds might be deployed
-kolla_base_distro: "{% raw %}{{ ansible_facts.distribution | lower }}{% endraw %}"
-
-# Convenience variable for base distro and version string.
-kolla_base_distro_and_version: "{% raw %}{{ kolla_base_distro }}-{{ kolla_base_distro_version }}{% endraw %}"
-
 # Dict of Kolla image tags to deploy for each service.
 # Each key is the tag variable prefix name, and the value is another dict,
 # where the key is the OS distro and the value is the tag to deploy.