The ProgramDb in the ElaboratedSharedConfig actually only ever contains
the programs configured by the compiler, and this is the way it will
remain, so rename to clarify that usage.

Config for other non-compiler programs will be handled differently. This
makes sense because the compiler (and programs) have to be shared
between all packages, while for non-compiler programs it's possible in
principle to use different versions for different packages within a
project. Thus it's not possible to have a single shared ProgramDb for
all programs for all packages (other than for the compiler).