Updated the settings for Tempest configuration

See the ticket [1] as the reason of the changes.

List of the main changes:

* Ability to set the CUSTOM_PUBLIC_NET_NAME - floating network
  in the offline and online methods of execution.
* The cvp.* flavors and images are not passed in tempest config.
* tempest_custom.yaml.clean file has reduced number of options
  (the old and irrelevant are removed).

[1] https://mirantis.jira.com/browse/PRODX-39383

Related-PROD: PROD-37187
Change-Id: I31e8c8e4b3d8eda706cbba46b4435d31f8f8eb4e
(cherry picked from commit ff980e1006dcfabc9622d0db7a6a0098f6ca03e4)
(cherry picked from commit 6b252d70db64ef5b981c18bc706fce712f1ce748)
diff --git a/k8s/yamls/tempest_custom.yaml.example b/k8s/yamls/tempest_custom.yaml.example
new file mode 100644
index 0000000..e105121
--- /dev/null
+++ b/k8s/yamls/tempest_custom.yaml.example
@@ -0,0 +1,45 @@
+auth:
+    tempest_roles: creator
+    admin_username: cvp.admin
+    admin_project_name: cvp.project
+    admin_password: mcp1234
+identity:
+    disable_ssl_certificate_validation: true
+compute:
+    fixed_network_name: cvp.net.1
+    flavor_ref: 1
+    flavor_ref_alt: 2
+    image_ref: image_ref_uuid
+    image_ref_alt: image_ref_alt_uuid
+    min_compute_nodes: 3
+    volume_device_name: vdb
+    compute_volume_common_az: nova
+object-storage:
+    endpoint_type: internal
+heat_plugin:
+    fixed_network_name: cvp.net.1
+    floating_network_name: public_net_name
+    network_for_ssh: public_net_name
+    fixed_subnet_name: cvp.subnet.1
+network:
+    subnet_id: public_subnet_uuid
+    public_network_id: public_net_uuid
+    floating_network_name: public_net_name
+network-feature-enabled:
+    floating_ips: true
+validation:
+    run_validation: true
+    ssh_timeout: 30
+    connect_timeout: 10
+    ping_timeout: 10
+    image_ssh_user: cirros
+    image_alt_ssh_user: cirros
+    image_ssh_password: gocubsgo
+    image_alt_ssh_password: gocubsgo
+    ssh_key_type: ecdsa
+octavia:
+    availability_zone: nova
+    availability_zone2: nova
+volume:
+    volume_type: volume_type_name
+    volume_type_multiattach: volume_type_name