Documentation Improvements

[jenniferjiangkells]

• Automate documentation publishing
• Make it more like "here's why YOU should use HealthChain..."
• Check code runs in doc snippets
• Add logo

So yes I made some changes in code in this PR that was supposed to be documentation. But I had to make those changes in order to get the code samples in the documentation to run and it's just the two of us so yeah just rolling with it.

CHANGES

• Set model dump exclude_unset to True - excludes all the fields with empties so that you don't send a huge file to your model
• Increase timeout for client - running local transformers on cpu takes a few secs. I actually just removed timeout for read operations but might want to pass this in as config in future.
• Removed markdown validation in CDSResponse - it's just too much effort for not high enough reward
• Moved docs dependencies out of pyproject.toml