trim space & unprintable characters from input fields

## Expected Behavior
when you are able to input IPs/hostnames or similar (in outputs & inputs) it should be possible to copy&paste cause those maybe included spaces are trimmed or the modal should not be able to be saved as long as invalid characters are in the field.

## Current Behavior
At least spaces can be part of the target server name/uri in the outputs what let Graylog fail to start those and spam the log with messages that this is not a valid target that can't be reached.

## Possible Solution
check the input and let the modal be saved only with valid chars and/or trim leading/trailing spaces

## Steps to Reproduce (for bugs)
1. Create Syslog Output
2. add a trailing space to the hostname
3. save & watch the log

## Your Environment

* Graylog Version: 3.3

[Z#843814]