Add support for DBEMask

[jacomago]

Allows opening different MonitorRequests
In particular for use in the archiver using DBE_ARCHIVE

Added a new pv to the demo.db that changes alarm frequently to test the DBE_ALARM in ClientDemo

Checklist

• Testing:

  • The feature has automated tests
  • [x ] Tests were run
  • If not, explain how you tested your changes

• Documentation:

  • The feature is documented
  • The documentation is up to date
  • Release notes:
    • Added an entry if the change is breaking or significant
    • Added an entry when adding a new feature

[jacomago]

Related to archiver-appliance/epicsarchiverap#328

[sonarqubecloud]

Quality Gate passed

Issues
9 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[jacomago]

@mdavidsaver fyi