Update tasks script
Minor scripts update (Python executable resolution)
Minor scripts update
Major packages refactoring

* Split `mosaic-platform-controller` into `mosaic-node`, `mosaic-node-wui`, and `mosaic-platform-core`.  (Use the latest one.)
* Remove `provides` (with the same value as the package name) from packages (it breaks OpenSUSE's Zypper).
* Add support for `env/paths` and `env/variables`.
Minor fixup