This is a simple renaming without adaptation.

Before this commit, if you or a lib uses Glyphicons, the font was loaded from
/web/content/fonts/ (or /web/static/src/less/fonts/ in debug=assets)

It is because bootstrap is imported from /web/static/src/less/import_boostrap.less
not directly from /web/static/lib/bootstrap/less/bootstrap.less

Now, we use absolute path to load font, overriding the variable define in
variables.less from bootstrap.

Properly style table’s rows ‘:hover’ state to let people understand
that it’s clickable

This commit basically reverts 4974f8edb76e27471bb00c1659c878d0b7a04daf
The fix was unstable (as restoring a feature that was not there
before release, even if originally merged before). This was in
particular breaking saas modals as lots of them are still opened
using 8.0 system... and opening them this way might make them appear
below their own backdrop in the new system the mentioned commit
restored.

We will think about that feature again for a future version.

Commit https://github.com/odoo/odoo/commit/7dcb8fea642858e0bb1d68cea9707cb3c8d4328d
(and https://github.com/odoo/odoo/commit/e64cf3d606bd94f7e0d82ec907ce7d1d66222287)
were supposed to make submodals backdrop appear on top of parent modals.

The feature was however broken by another commit before it was released:
https://github.com/odoo/odoo/commit/f997c128c7295b5e76d7f77d79c4a82898debbcf

- bg-*-full color classes were only defined in enterprise while they
  should have been defined here (fixes kanban column progressbars)
- new @gray-lighter variations should be defined in variables.less
  as they are bootstrap extensions, not bootstrap overrides

This is also meant to solve a bug in firefox: the scrollbar was the
same color as the background by bad luck.

+ Adapt kanban view borders