This is a huge configuration refactoring.
The configuration system now uses Pydantic settings, with better validation, better
support for environment variables and other goodies.
The main config files now use TOML instead of INI, this allow for better handling of
complex types, notably dict.
Plugins, components and frontends can declare their config settings in a class which will
be imported dynamically.
- Code has been rewritten using Pydantic models and `async` coroutines for data validation
and cleaner element parsing/generation.
- Delivery has been completely rewritten. It now works even if server doesn't support
multicast, and send to local multicast service first. Delivering to local multicast
service first is due to bad support of XEP-0033 in server (notably Prosody which has an
incomplete implementation), and the current impossibility to detect if a sub-domain
service handles fully multicast or only for local domains. This is a workaround to have
a good balance between backward compatilibity and use of bandwith, and to make it work
with the incoming email gateway implementation (the gateway will only deliver to
entities of its own domain).
- disco feature checking now uses `async` corountines. `host` implementation still use
Deferred return values for compatibility with legacy code.
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