Leaflet Javascript Library

This module extends odoo to include Leaflet Javacript library.

This module is used by `web_view_leaflet_map`.

**Important Note**

The javascript library is opensource and distributed under BSD 2
Licence. See : <https://github.com/Leaflet/Leaflet/blob/main/LICENSE>.
The plugin library is opensource and distributed under MIT
Licence. See : <https://github.com/Leaflet/Leaflet.markercluster/blob/master/MIT-LICENCE.txt>.

You can so use it freely.

However, display maps requires to display layers provided by tiles
servers, that requires ressources.

**For testing purpose**

You can use the openStreetMap url
`https://tile.openstreetmap.org/{z}/{x}/{y}.png` or other, listed in
that page : <https://wiki.openstreetmap.org/wiki/Tile_servers>

Apart from very limited testing purposes, you should not use the tiles
supplied by OpenStreetMap.org itself. OpenStreetMap is a volunteer-run
non-profit body and cannot supply tiles for large-scale commercial use.

**Regular / High Usage**

- you can contact one of the following companies :
  <https://switch2osm.org/providers/>
- You can also install yourself your own tiles servers. See
  documentation : <https://switch2osm.org/serving-tiles/>

**Library Update**

For the time being, the module embed the lealflet.js library version
1.9.4 ( released on May 18, 2023.)

If a new release is out:

- please download it here <https://leafletjs.com/download.html>
- update the javascript, css and images, present in the folder
  `static/lib/leaflet`
- update the plugins
- test the features
- make a Pull Request