This addresses issues with image dropping and pasting.
1. The code to compute the position of the drop was not always run so
that resulted in a sometimes wrong position (dropping at current range
instead).
2. Images dropped internally within a same document should not be
converted to base64.
3. Dropping an image should apply to it the `img-fluid` class so as not
to break the document's layout.
task-2954499
closesodoo/odoo#105137
X-original-commit: 9c258bf18c17a55f1d22c8a7d1b74f5dd51ee73d
Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>