Use conventions file in repo as read-only context

[larryhudson]

Currently, we don't use any contextual information from the repo in our prompt. I think it would be good to check if a 'conventions' file exists in the repo, and add that as 'read-only' context in Aider before running our coding prompt.

I think the way we would do this is:

• add an environment variable for a 'conventions file path' which would be relative to the repository project root. Example: './CONVENTIONS.md'
• when the git repo is cloned, check if that environment variable is set, and if that file path exists. if it does, then pass that in the 'Coder.create' call in the read_only_fnames parameter.

That should be all we need to change to make this work.

@Aiderbot could you have a look at this?

[larryhudson-aider-github[bot]]

I've created a pull request to address this issue: https://github.com/larryhudson/aiderbot/pull/61

Time taken to create this PR: 78.38 seconds