fix(virtual_server_group): add virtual_server_group to template

[WojciechOzog]

### PR progress checklist (to be filled in by reviewers)

• Changes to documentation are appropriate (or tick if not required)
• Changes to tests are appropriate (or tick if not required)
• Reviews completed

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What type of PR is this?

Primary type

• [build] Changes related to the build system
• [chore] Changes to the build process or auxiliary tools and libraries such as documentation generation
• [ci] Changes to the continuous integration configuration
• [feat] A new feature
• [fix] A bug fix
• [perf] A code change that improves performance
• [refactor] A code change that neither fixes a bug nor adds a feature
• [revert] A change used to revert a previous commit
• [style] Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc.)

Secondary type

• [docs] Documentation changes
• [test] Adding missing or correcting existing tests

Does this PR introduce a BREAKING CHANGE?

No.

Related issues and/or pull requests

Describe the changes you're proposing

This change provide to use virtual_server_group param in pillar because without this it doesn`t work - it does not exist.

You must use virtual_server_group as workaround in case if You have two same server_group (same ip, same port but diffrent protocol - dictionary key error)

Pillar / config required to test the proposed changes

keepalived:
  config:
    vrrp_instance:
      LVS0:
        state: MASTER
        virtual_router_id: 1

    virtual_server_group:
      dns_TCP:
        - 10.10.10.53 53
      dns_UDP:
        - 10.10.10.53 53

    virtual_server:
      group dns_TCP:
        protocol: TCP
        real_server:
          10.10.10.1 53:
            weight: 100

      group dns_UDP:
        protocol: TCP
        real_server:
          10.10.10.1 53:
            weight: 100

Debug log showing how the proposed changes work

Documentation checklist

• Updated the README (e.g. Available states).
• Updated pillar.example.

Testing checklist

• Included in Kitchen (i.e. under state_top).
• Covered by new/existing tests (e.g. InSpec, Serverspec, etc.).
• Updated the relevant test pillar.

Additional context