Restore 'emencia_initial' feature

[sveetch]

No description provided.

[sveetch]

I'm trying a new way without migrations since they caused too much problems.

Instead we are going to a "demo maker" which can load objects from a data structure that could work both with command and tests.

[sveetch]

It's on the way to be finished in branch "initial_migrations" but this won't be flexible as the project composition.

Tests and demo maker are currently not fail safe when CMS is not enabled. Think to fill an issue about flexbiility without CMS.

[sveetch]

Currently working with test and django command within current working branch initial_migrations.

However the DemoMaker take only on page at level 0 (from given page tree structure) which it assumes as the root page and so this avoid to have other pages at level 0 even if it is totaly valid and common use case.

We should introduce a "is_homepage" in page structure format, stop take the first level 0 as homepage, and process all other page level 0.