Is your feature request related to a problem? Please describe.
Some of my keys are composite and the components are separated by tab characters or the Zero character. I can insert a tab character into the 'Key separator' field by cut and paste. However the zero char I'm not sure.

Describe the solution you'd like
To avoid the above workaround and to fully support non-printable keys, I request that the 'Key separator' field will understand defacto standard character escape sequences, JSON format would be an obvious choice. So it would allow \u0000 , \t \n etc

Describe alternatives you've considered
'C', Java escape sequences.

Additional context
IDK if this is already documented somewhere. Also, etcd uses byte for keys and values. Can etcd manager cope with binary keys and values? Is there a hex option? IDK...