Remove double datamodel definition

[olivierdalang]

Currently, datamodel is defined both as init scripts and through deltas, leading to a duplicate definition that often gets out of sync.

We should remove the datamodel definition, and only keep deltas. This requires adapting PUM so it is able to initialize an empty database and adding an initial 1.0.0 delta.

Note: we can keep an SQL representing the full datamodel as a build artifact for documentation purposes.

[sjib]

Note: we can keep an SQL representing the full datamodel as a build artifact for documentation purposes.

I would still provide this as a mandatory requirement - if you just want to setup the datamodel seperately somewhere (testing or whatever, where you do not have the pum tools available to go with all the deltas)