The document layout preview is a complete defferent simplified template
with its own css that replicates at best the different styles.
It does not have the external layout features and lack of fidelity.

The new preview actually use the real documents templates and put the
result in an iframe. It now has a high fidelity, though not perfect.

The goal is for a better onboarding, where clients see easely how
documents will look if they had an app to generate them. Of course, the
data on the document is a false invoice.

Refactor all this from base to web.

Task ID 2304177

closes odoo/odoo#56415

Signed-off-by: Lucas Perais (lpe) <lpe@odoo.com>

The onboarding modal for setting up the few base fields of a company
has now been moved to a wizard
It is accessible from the general settings, but also in the onboarding
section of sale and account modules.

The following company settings are editable with that wizard:

- Set report **layout**:
The user can chose the overall look of the report. The current choices
are : *Standard* (default), *Background*, *Boxed* and *Clean*.

- Set company **logo**:
Changes the company logo.

- Set report **colors**:
The user can set the primary and secondary colors of the report through
a newly added widget allowing to pick a custom color.
When changing the **logo**, colors are automatically set to its most dominant
colors.
> A "Reset colors" button also triggers the color calculation.

- Set report **font**:
Changes the overall font of the report. Only Google Fonts are used
for enhanced compatibility.

- Company **tagline**, also called "header"
- **Footer**
- **Paper format**
- Report **preview**:
A mockup of a final report
Automatically updates when changing **layout**, **logo**, **colors** or **font**

Co-authored by: Julien Mougenot <jum@odoo.com>

closes odoo/odoo#33863

Signed-off-by: VincentSchippefilt <VincentSchippefilt@users.noreply.github.com>


Co-authored-by: Lucas Perais <lpe@odoo.com>

Before this rev. one could set the report layout on the company using a
hardcoded list (background, clean, standard, etc.). Other modules (typically
accounting modules) could add options in this list. The used template was built
on the layout key.

Now, the layout is a many2one field to a newly created model `report.layout`,
which is linked to a view with the layout architecture.

This gives more control to customize reports and create a new layout (without
creating a python module that extend the layout selection).