Force development only web console by default

[gsamokovarov]

People are starting to hit more and more issues of running Web Console
in the test environment. I'm sure some people still try to even run it
on testing and staging environments, even through we try to preach
against it. I don't like that we add yet another configuration, as we
have quite a bit of those, but I think the new default behaviour is
beneficial to the users.

I tried to put a good message guiding the user should they try to use
Web Console outside of the development environment. It also includes
information on how to force the usage.

Requiring web-console outside of development will result in process
quitting with the following message:

Running Web Console outside of development isn't recommended. Please,
keep it in the development group of your Gemfile.

If you still want to run it and know what you are doing, put this in
your Rails application configuration:

config.web_console.development_only = false

Any suggestions on the grammar are welcome. Pinging @sh19910711 for
review and @matthewd who raised concerns about this as well.

[sh19910711]

LGTM 👍