Doc(eos_cli_config_gen): Improve snmp server documention

[carlbuchmann]

Change Summary

When configuring snmp_server.hosts, the community is required to be defined when a version is 1 or 2c but not version 3.
Improving the documentation to make this more clear.

See template:

{%     if snmp_server.hosts is arista.avd.defined %}
{%         for host in snmp_server.hosts | arista.avd.natural_sort('host') %}
{%             if host.host is arista.avd.defined %}
{%                 set host_cli = "snmp-server host " ~ host.host %}
{%                 if host.vrf is arista.avd.defined %}
{%                     set host_cli = host_cli ~ " vrf " ~ host.vrf %}
{%                 endif %}
{%                 if host.users is arista.avd.defined
                      and host.version | arista.avd.default('3') | string == '3' %}
{%                     for user in host.users %}
{%                         if user.username is arista.avd.defined
                              and user.authentication_level is arista.avd.defined %}
{{ host_cli }} version 3 {{ user.authentication_level }} {{ user.username }}
{%                         endif %}
{%                     endfor %}
{%                 elif host.community is arista.avd.defined
                        and host.version | arista.avd.default('2c') | string in ['1', '2c'] %}
{{ host_cli }} version {{ host.version | arista.avd.default('2c') }} {{ host.community | arista.avd.hide_passwords(hide_passwords) }}
{%                 endif %}

Related Issue(s)

Fixes #4802

Component(s) name

arista.avd.eos_cli_config_gen

[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-4806
# Activate the virtual environment
source test-avd-pr-4806/bin/activate
# Install all requirements including PyAVD
pip install "pyavd[ansible] @ git+https://github.com/carlbuchmann/avd.git@fix-doc-4802#subdirectory=python-avd" --force
# Point Ansible collections path to the Python virtual environment
export ANSIBLE_COLLECTIONS_PATH=$VIRTUAL_ENV/ansible_collections
# Install Ansible collection
ansible-galaxy collection install git+https://github.com/carlbuchmann/avd.git#/ansible_collections/arista/avd/,fix-doc-4802 --force
# Optional: Install AVD examples
cd test-avd-pr-4806
ansible-playbook arista.avd.install_examples