pgAdmin 4 commit: Move the config database schema version out of the co

Move the config database schema version out of the configuration file and into the model class.

Turns out using the config file isn't a good idea if users copy config.py to config_local.py, as it prevents upgrades
tothe database. This has the added side-effect of simplifying future changes, as you only need to edit 2 files to
modifythe config DB now, not 3. 

Branch
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master

Details
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http://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=d63b54610b8b70aae781196a5acee24e4f39c307

Modified Files
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web/config.py                 |  4 ----
web/pgAdmin4.py               |  5 +++++
web/pgadmin/model/__init__.py | 18 +++++++++++++++++-
web/setup.py                  |  5 +++++
4 files changed, 27 insertions(+), 5 deletions(-)