Docker compose cleanup

[Jamie-Clayton]

What this PR does / why we need it:

• Refactor the .env secrets file used by docker compose
• Add instructions to the readme file for the solution to explain how to perform local testing of the code.
• Add yaml-language-server references for a better developer experience.
• WIP : More commits are required to get everything working in docker desktop.

Which issue(s) this PR fixes:

• Contributes to solving Docker-Compose out of date and makes integration testing difficult #2247

Special notes for your reviewer:

• Recommend: Install the Redhat Yaml extension in Visual Code
• Further .editorconfig preferences should be considered for yaml files.

[*.{yml,yaml}]
indent_style = space
indent_size = 2
end_of_line = lf
charset = utf-8
trim_trailing_whitespace = true
insert_final_newline = true
spaces_around_brackets = true

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Unit tests passing
• End-to-end tests passing
• Extended the documentation
• Provided sample for the feature