Drop views before pum upgrade

[ponceta]

Description : To avoid having to write deltas for every view change, drop views before any pum upgrade as done for TEKSI drinking water module.

Linked issue :

• [x] https://github.com/QGEP/QGEP/issues/798

Linked Pull requests :

• [x] https://github.com/QGEP/datamodel/pull/146