Remove support for automatic conversion from dict-of-dicts to list-of-dicts

[ClausHolbechArista]

Remove support for automatic conversion from dict-of-dicts to list-of-dicts in both eos_designs and eos_cli_config_gen. This should be split into multiple PRs as needed.

eos_designs:

• Remove convert_types: [dict] from schema
• Remove convert_dicts() from Python code.
• Clean up deprecated tests if they are only testing the old dict models.

eos_cli_config_gen:

• Remove convert_types: [dict] from schema
• Remove | convert_dicts from Jinja templates.
• Clean up deprecated tests if they are only testing the old dict models.

General

• Identify schemas with convert_types: [list] since these may also rely on convert_dicts code.
• Remove avd_data_conversion_mode from
  • schemas
  • Ansible plugins
  • PyAVD
  • Documentation
• Update release-notes + porting-guide with this change
• Clean up schema tooling to longer convert dicts and lists and no longer emit deprecation and conversion warnings