Create new metapackage to track application dependencies for sd-viewer based dispVMs

[eloquence]

We're currently tracking applications required in sd-viewer dispVMs in the securedrop-workstation-svs-disp package.
https://github.com/freedomofpress/securedrop-debian-packaging/blob/main/securedrop-workstation-svs-disp/debian/control#L11

As part of template consolidation (freedomofpress/securedrop-workstation#471), we've agreed that it would make sense to add a separate metapackage that specifies these dependencies, without including the current package's contents, as these will no longer be required once consolidation is complete. securedrop-workstation-svs-disp can be removed in the final stage of the template consolidation process.

NB: This new package should no longer use the svs abbreviation in its name, which is deprecated in the context of the SecureDrop Workstation.

[eloquence]

Should include CI target to build the package.