Filtering logs per sink

[Yamboy1]

It would be nice to be able to filter which logs go to which sink. There are a lot of possibilities of how this would work, so this might be pushed past the v1 milestone.

Possible options:

• Filter by log level
• Filter by paramters
• Filter by format string
• Filter by the value of a specific paramater

It would be nice in the end to support most, if not all of thse, and maybe more in the long run.