First, there is no need to "patch" the registry before setting up models: the
setup of models will rebuild the custom models and fields in registry.

Second, invalidate the registry cache for manual fields after updates.  This
guarantees a clean setup of models after the changes.

Main changes summarized

product
- [REM] weight_net field. Weight net is removed from the product model.
Indeed a product should be modeled without its possible packaging data.
Moreover in the codebase the weight_net field is not really used.
- unused import
- removed _common.py file holding wrappers for tools (rouding and
ceiling), used only once in the codebase

purchase
- unused imports

purchase_requisition
- dead code
- purchase_requisition: from boolean to selection, because V > M

stock
- [REM] qty_available2, logic, loc_rack, loc_row, loc_case fields. location_id
and warehouse_id moved from the product to the template to ease the
configuration.
- [ADD] description_picking field

stock_account
- [REM] date_account field on stock.inventory

misc wording (sale_margin, ...), notably Cost Price renamed to Cost.

[FIX] account: invoice related usability changes. Add of signed fields to display the residual and total amounts of refunds with a negative sign, fixed the invoiced button on partners, fixed the numbering for refunds

User can upload documents and add the link in the page to download it.

Widgets and website display images or display the type with icon like pdf, doc...

Replace deprecate controllers like /web/binary/image, /web/binary/saveas...
Use ETag for all content with 'unique' option to cache the content if the content is never changed.

This reverts commit 75140d7e.

When a bank statement acquisition method (file import, plaid, manual encoding)
is used on a journal, it should only be set as the journal's
bank_statements_source after successful completion.

id of the partner / channel is now res_id. id is the id of the follower
entry itself.

probably introduced in a rebase or something; not imported anywhere anyway

Convert help field on an ir.action to html as it was already used do display
html messages.
Converting it to html allows to benefit from changes made at 75140d7e for better
translation of help message.

(backport from the enterprise version)
The M2ODialog still used the old Dialog API.

LESS rules (enterprise compatibility) :
* .oe_avatar is float:left by default
* .oe_title is placed between oe_avatar/oe_button_box if any
without the need to make it float

* listing of modules in website already bypassed session user
* altered authenticated endpoint so it does the same
* sudoed a few read accesses & name_get in groups
* other accesses are list/form views, menu only accessible to
  system_user
* new-API-ified some calls & unified listing of installed modules

from 500 to 1000, as requested by fp

Main changes :
- mail.notification model is removed. People do not receive notifications
anymore. Instead two ways of following documents exist
  - using a channel; messages will be displayed on the channel itself
  in a near future commit
  - following with its partner; messages will all be considered as
  needaction, using a new m2m table. People should receive less
  needaction messages by following less records by themselves.
There is no more read / unread state anymore. Instead only needaction
messages are considered. Todo (Favorites) messages still exist, and are
stores on a new m2m table instead of using decorated notifciations.
- the main filter for documents is not message_unread anymore, but
message_needaction. A lot of views and filters have been updated
accordingly.
- the vote feature has been removed

Some features from live_chat have been moved to the mail module :
- channels now have members, replacing followers;
- a decorated m2m is used to link channels and members. It stores the last
seen message on the channel for a specific partner;
- channels do not create menu entries anymore, because the
NewChatter will have its own display and use of channels;
- access rights have been updated accordingly, using members instead of
followers