feat(SDM): Ability to accept Python code with `config.json`

[aaronsteers]

We currently pass manifests to SDM in a special config key __injected_declarative_manifest.

This proposal would add three new special config keys:

1. __injected_components_py (str): Optional. The full text of a components.py file.
2. __injected_components_py_sha256 (str): Optional. Hash of the components.py text file. When provided, it will be validated against the __injected_components_py contents. Execution will abort if the checksum does not match.
3. __allowed_hosts (list[str]): Optional. List of hosts to which the connector should restrict outgoing traffic. When provided, outgoing http requests will not be allowed if they are outside of these allowed hosts.

This would be backwards compatible and not requiring any new capabilities in the platform. This makes our config.json contents much larger, but otherwise it doesn't break anything or open up new vulnerabilities.

Note:

• Note that __allowed_hosts can optionally be deprioritized and moved into a separate issue. In terms of effort, there is not much overlap in functionality between the ability to run custom code and the ability to restict network traffic. The higher priority is being able to run custom python code from SDM.