Avoid logging for some "paths"

[dlnsk]

It would be really convenient to avoid logging for some paths, such as /health which is called every minute and fills the log by spam.

-avoid-log-for=health,some-other

[msoap]

The goal of this project is to remain as simple as possible. If there is a way to do something using the shell, it's better to do it that way rather than adding a new option in the code. Specifically in this case, you can use "grep -v" to exclude lines.

Example:

shell2http /date date /health 'echo ok' /another 'echo 2' 2>&1 | grep -Ev 'GET /health|GET /another'

[dlnsk]

Pipes is a bad idea for docker, because of PID is not 1, sh don't support pipefail and grep may buffering output.