Feat(eos_designs): Add support for 'uplink_mtu' under node config

[laxmikantchintakindi]

Change Summary

It is currently not possible to set the uplink mtu to dedicated leaf node or node group.
This change will add uplink_mtu for node_group and node settings.

Related Issue(s)

Fixes #3985

Component(s) name

arista.avd.eos_designs

Proposed changes

Add option uplink_mtu under node_config.

# Define variables related to all nodes part of this group.
node_groups:
    # Override the default `uplink_mtu` set at the `node_type_key` level.
    uplink_mtu: <str>

    # Define variables per node.
    nodes:
        # The Node Name is used as "hostname".
      - name: <str; required; unique>

        # Override the default `uplink_mtu` set at the `node_type_key` level.
        uplink_mtu: <str>

How to test

Add key uplink_mtu under node_groups or node settings. Verify configuration.

Checklist

User Checklist

• N/A

Repository Checklist

• My code has been rebased from devel before I start
• I have read the CONTRIBUTING document.
• My change requires a change to the documentation and documentation have been updated accordingly.
• I have updated molecule CI testing accordingly. (check the box if not applicable)

[github-actions]

Review docs on Read the Docs

To test this pull request:

# Create virtual environment for this testing below the current directory
python -m venv test-avd-pr-4040
# Activate the virtual environment
source test-avd-pr-4040/bin/activate
# Install all requirements including PyAVD
pip install "pyavd[ansible] @ git+https://github.com/laxmikantchintakindi/avd.git@uplinkmtu#subdirectory=python-avd" --force
# Install Ansible collection
ansible-galaxy collection install git+https://github.com/laxmikantchintakindi/avd.git#/ansible_collections/arista/avd/,uplinkmtu --force
# Optional: Install AVD examples
cd test-avd-pr-4040
ansible-playbook arista.avd.install_examples

[ClausHolbechArista]

Minor comments, but overall looks good to me.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[ClausHolbechArista]

LGTM. Thanks

[Shivani-gslab]

LGTM