[FIX] avoid inserting invisible filters

and avoid inserting two separators because of that
[FIX] various small UI tweaks
[IMP] various code improvements

mostly styling, and related micro-changes
[FIX] correctly check default/shared filters

in searchview.  They were swapped in the UI, and not in the code.  It
also shows that using position as reference is fragile.
[REM] remove instance.web.ViewManagerAction

ViewManager takes over all duties of ViewManagerAction, it can now be
safely removed.
[IMP] xml, css and js tweaks in advanced search view
[FIX] hide groupby menu in inbox (addon mail)

the groupby menu does not do anything in the client actions.  Hiding the
group by menu prevent possible confusion about its use.
[FIX] css and layout fix in advanced search view

* make sure the searchbar allows text selection
* revert back to col-md (from col-lg) classes => looks better
[IMP] better variable/function names in action manager
[IMP] move some functions in a better position (web client)

the prepare_search_inputs is an initialization function, and was at
the end of the Searchview class.  It is more intuitive to put it closer
to the top
[DOC] cmdline: database-related parameters
[FIX] point_of_sale: no need to specify numeric digits

In the report pos order, average_price was set as a numeric(16,2), therefore, if the amount was too big, it led to a psql crash:
A field with precision 16, scale 2 must round to an absolute value less than 10^14.
[MERGE] Improved search view UI

This branch is the result of a UI rethink of the search views.
In order to do that, many other parts had to be moved/reworked.
Main changes affect action manager, view manager and search view
(they have been almost completely rewritten)

Some highlights:
* search view has 3 submenus (filters, groupbys, favorites) and all inputs are included in these submenus
* view manager header is now responsive, and bootstrapized
* icons are now using fontawesome
* transitions between views should have much less flicker (because of work in action and view managers)
* debug mode has a pretty icon (because why not)
* we can now add custom groupbys (every groupable fields from the model are exposed (make sure you have good descriptive strings))
[MERGE] forward port of branch 7.0 up to 78a29b3
[MERGE] forward port of branch 8.0 up to d80376a
[IMP] web_graph: renamed Quantity field into Count to avoid ambiguities
[MERGE] forward port of branch 8.0 up to 262eb66
[FIX] report: page numbering rml reports

Save the NumberedCanvas state before doing a page reset.
The order of execution when rendering an rml report is the following:
1. init canevas (_pageNumber = 1)
2. render the page element
3. if still pages to render, afterPage method
4. if still pages to render, showPage method (_pageNumber += 1)
5. back to step 2 for each page
6. draw the ResetPage element (setting flag _doPageReset=True)
7. end the document build with afterPage & showPage method

The PageReset element should be executed at the end of the rendering of a story (subdocument) to reinitialize the page numbers to 0 (for new story) and insert the pageCount element for that story with the total number of pages (needed if want to use tag <pageCount/> in rml).

In case of NumberedCanvas (e.g. used in Trial Balance report), the numbering is generated at the end of the build using the _saved_page_states dict in the canevas.
To have an accurate _saved_page_states content, it needs to be saved before the pageReset.

Fixes #2225
[FIX] website_certification: no need to set a group to acl if the data is public
[IMP] project: convert file CRLF to Unix end of line