Clean up config and generate Evolutions

Configuration has been broken up into different files that are imported in
(included) onto the main configuration file (application.conf) as needed.
Currently, the only one separation is database connection parameters, into
"db-default.conf" and "db-test.conf". Default database configuration has also
been secured up by using environment variables instead of using a config file
for URL, user and passowrd; it's not relevant right now, since it is just in
development mode, but it will be when pushed onto production.

Also tracked Slick-generated SQL evolution files for default and test databases
into this git repository.
Add Base class to all test specs

Abstract base class BaseSpec is created to be inherited by all test classes. It
simplifies the mixin of multiple ScalaTest traits into just one common class
that every test class should inherit from.