[Feature] Support Trio

[merlinz01]

Currently Tortoise only supports code using the stdlib asyncio framework. I have a project that uses the trio async framework and I wanted to use Tortoise for the database functionality but ran into errors from Tortoise using asyncio.

The changes required to support trio would be substituting asyncio with the anyio package. This would most likely require some API changes to support the structured concurrency patterns used in trio/anyio.

I likely won't end up using Tortoise in my trio-based project, at least for now, but I wanted to open this issue to see whether this might be possible to support.