Add more configuration variables

[thinkofher]

By adding more configuration variables we chould make long-season less "hakierspejs" specific. It isn't something bad, but this piece of software may be useful for other *spaces in future.

My proposition for new variables:

• LS_CITY - will be shown after @ sign at the navbar #66
• LS_SPACE - will be shown before @ sign at the navbar #65
• LS_IGNORE - comma separated list of blacklisted MACs; Add a way to "blacklist" MACs #28

You don't have to commit code for front-end[1] right now. Adding more variables to config module is enough. Take a look at existing configuration variables if you need example (LS_HOST or LS_PORT).

[1] But you can if you want :)

[thinkofher]

city and space can be added to /api/v1/status endpoint or /who