[FIX] web: css tweaks
[IMP] hr modules: needaction, subtypes and department-based improvements.

This commit prepares some cleaning in various hr-related modules that are
about to land in master. There are mainly improvements on subtypes. The
subtypes are now linked to department subtypes, allowing to follow some records
based on the department (like project/task/issue).
[FIX] point_of_sale: On product form : push on button 'Set a Custom Ean' on tab information raise an exception => Use a record action and clean python files
[FIX] web: fix tooltip that were stuck visible

tooltip stuck visible should be removed on click + remove tooltip container except for modal in order to prevent them for staying visible in some rare occasion
[FIX] account: on_change_unit_amount do not reset uom to default
[MERGE] forward port of branch 7.0 up to cd31cbf556cc11950ce6188041cf5c2fcd89e0f8
[FIX] account: unit arg of on_change_unit_amount can be False
[MERGE] forward port of branch 7.0 up to 7c5bf67a5f9378fe4ae01eeffff24889f7bdcdc5
[FIX] crm: base_partner_merge, search with lowercase for name,email

and without spaces for vat
[FIX] mail: message-id not parsed properly in message_route

Same as for rev 4bad513, the references were not correctly parsed, added missing regex
[FIX] account: avoid to propagate context in send by email button

There is no reason to propagate the context in those buttons.

Besides, it leads to issues concerning the email template, rendering the wrong res_id because the active_id was wrongly propagated
[FIX] event: registration and confirmation template now have a domain on event.registration.
Otherwise all templates are displayed and this will lead to some issues.

Also added a description on event.registration, because currently its
displayed name is Email Thread.
[FIX] mass_mailing: allow to add a user/email to a specific mailing list and not always the last as previously.
[FIX] web: remove unneeded overflow-y on modal-body class

Will fix problem where opened dropdown list were hidden behind the modal footer
[FIX] website: the media video create by the media editor is not display in firefox. change the css to display the video and add z-index to the div for edit mode
[FIX] orm.search_count: ignore `limit`, `offset` and most importantly `order`

These parameters are (or should be) irrelevant for
a search_count(), and they could actually break the
result or make it significantly slower (e.g applying
`order` on large tables).
This fixes a performance regression introduced by
0f43032b.

We could also raise an error offset/limit are
passed in combination with count, but that seems
unnecessary.

Also switched to "SELECT count(1)" for the count
query, as it is simpler and just as fast.
We'd get the same perf with * or any constant value,
as in "SELECT count('me in')", but let's keep it
simple ;-)
[MERGE] Forward-port saas-3 up to e79a367
[MERGE] Forward-port saas-4 up to 8b15482
[FIX] mail: bad display of join button on mail groups.
[FIX] mass_mailing: possibility to subscribe again to a mailing list

It was not possible to subscribe again to a mailing list once unsubscribed