pgAdmin 4 commit: Introduced a PgAdmin class inherited from the Flask,

Introduced a PgAdmin class inherited from the Flask, which looks for
submodules inherited from the PgAdminModule instead of regular
Blueprint. This allows us to load the module automatically from the
under the pgadmin directory, and will work to extend the pgAdmin
extension module.

PgAdminModule is inherited from the Blueprint, and bring several
methods:
-  get_own_stylesheets, which returns the stylesheets used by the module
   (excluding its submodules stylesheets)
- get_own_javascripts
- menu_items, which returns a dictionray mapping the old hook names
  (context_items etc) to a list of MenuItem instances

For more specialized modules (as for now, any module that should be part
of the browser tree construction), one can define an abstract base class
defining additional methods.

For example, the BrowserPluginModule abstract base class defines the
following methods:
- jssnippets
- csssnipeets
- node_type
- get_nodes

Branch
------
master

Details
-------
http://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=eb6580b43a25bc0f1ade2e2c0c66c34d3cd87f81
Author: Ronan Dunklau <ronan.dunklau@dalibo.com>

Modified Files
--------------
web/pgAdmin4.py                                    |    8 +-
web/pgadmin/__init__.py                            |  109 +++++-----
web/pgadmin/browser/__init__.py                    |  159 ++++++++++++++-
web/pgadmin/browser/hooks.py                       |   21 --
web/pgadmin/browser/server_groups/__init__.py      |  202 +++++++++++++++++-
web/pgadmin/browser/server_groups/hooks.py         |   78 -------
.../browser/server_groups/servers/__init__.py      |  166 ++++++++++++++-
web/pgadmin/browser/server_groups/servers/hooks.py |   72 -------
web/pgadmin/browser/server_groups/servers/views.py |  121 -----------
.../templates/server_groups/server_groups.js       |    2 +-
web/pgadmin/browser/server_groups/views.py         |  129 ------------
.../browser/templates/browser/css/browser.css      |    3 +
web/pgadmin/browser/templates/browser/css/node.css |    3 +
web/pgadmin/browser/templates/browser/index.html   |    2 +-
.../browser/templates/browser/js/browser.js        |  160 +++++++--------
web/pgadmin/browser/views.py                       |  214 --------------------
web/pgadmin/misc/__init__.py                       |   25 +++
web/pgadmin/misc/views.py                          |   27 ---
web/pgadmin/redirects/__init__.py                  |   19 ++
web/pgadmin/redirects/views.py                     |   29 ---
web/pgadmin/settings/__init__.py                   |   85 +++++++-
web/pgadmin/settings/views.py                      |   83 --------
web/pgadmin/templates/base.html                    |   16 +-
web/pgadmin/utils/__init__.py                      |   80 ++++++++
web/pgadmin/utils/menu.py                          |    6 +
25 files changed, 876 insertions(+), 943 deletions(-)