[Feature] Multiple locations for migration files

[snimshchikov]

I find aerich tool very useful but my migrations/models folder contains 25 migrations files, which makes it difficult to manage. Would be nice if I could specify multiple locations for migration files (./migrations/v1 ./migrations/v2 etc).

Something like

[tool.aerich]
tortoise_orm = "db.database.TORTOISE_ORM"
location = "./migrations/v3"
readonly_locations = ["./migrations/v1", "./migrations/v2"]
src_folder = "./."

[waketzheng]

These two lines looks strange: location = "./migrations/v3"
readonly_locations = ["./migrations/v1", "./migrations/v2"]

Cloud you show the result of python -c "import db;print(db.database.TORTOISE_ORM)"