Made the technician config more customisable

 * Can decide whether the tech user is native or webmin
 * Can change tech user name & password

This change needs to be discussed before it can be finalised

Issue: IWsoftware/ekahau-rtls-playbook#1
Ticket: #5507

Signed-off-by: Nathan Callister <ncallister@iwsoftware.com.au>