Script server: Allow read-only access

Currently NICOS can be accessed through a password protected ActiveMQ queue, the password for which could be served up as described in https://github.com/ISISComputingGroup/IBEX/issues/1995. This will be the method for read/write access.

A separate access method should be created that allows read only access to NICOS. To do this we need to:
- [ ] Add a read-only script server queue to our activeMQ config
- [ ] Create a read-only account in the NICOS config
- [ ] Modify the script server proxy to accept commands from the new queue and log in to NICOS under the read-only account

A follow up ticket will configure the GUI to use this.

Start by locating the ActiveMQ configuration, NICOS configuration, and script server proxy mentioned in the checklist. Trace how the existing password-protected queue authenticates and handles commands. Done means a separate queue and NICOS read-only account are configured, and the proxy accepts that queue while using the read-only account.

Scritto dal modello di indicizzazione a partire dal testo della issue.