Introduce build of a new taped, using new type of SchedulerDatabase
This issue is intended to be the first step in making a new scheduler database; to include the build a new cta-taped which will use a new class derived from SchedulerDatabase. It is imagined that this will be Postgres based, but the scope of this first issue to setup a new derived class with minimum content (e.g. giving not supported errors for all methods) along with the new, separate taped binary. Existing binaries and functionality should not be changed.
EDIT:
Scope of issue slightly changed to enabling the replacement of the objectstore based scheduler with another scheduler. So this implies that, when enabled, the cta-taped will be built using the new scheduler not that an additional binary is built. The change is also larger than specifically cta-taped, but impacts all components with scheduler dependency such as libXrdSsiCta.so, cta-tape-label, cta-readtp, frontend-grpc and the various unit tests. A CI pipeline variable is also foreseen to enable CI tests of the build with the new scheduler.