Implement/test LOLWUT command

[brainix]

Pull Request check-list

• Does $ tox pass with this change (including linting)?
• Does travis tests pass with this change (enable it first in your forked repo and wait for the travis build to finish)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?

Description of change

Implement/test LOLWUT command

This is a lot of fun to play with:

>>> from redis import Redis
>>> redis = Redis()
>>> print(redis.lolwut(5, 6, 7, 8).decode('utf-8'))
⣴⣶⣶⣶⣶⡆
⣿⣿⣿⣿⣿⡇
⠹⡿⠟⣿⡿⠃
⠀⠀⠀⠀⠀⠀
Georg Nees - schotter, plotter on paper, 1968. Redis ver. 6.0.10

>>> print(redis.lolwut(5, 6, 7, 8).decode('utf-8'))
⢰⣶⣶⣶⣶⡆
⢿⣿⣿⣿⣿⠁
⠸⡿⢿⠿⡿⠃
⠀⠀⠀⠀⠀⠀
Georg Nees - schotter, plotter on paper, 1968. Redis ver. 6.0.10

>>> print(redis.lolwut(5, 6, 7, 8).decode('utf-8'))
⢰⣶⣶⣶⣶⡆
⣸⣿⣿⣻⣿⡅
⠿⡿⠻⠿⠿⠁
⠀⠀⠀⠀⠀⠀
Georg Nees - schotter, plotter on paper, 1968. Redis ver. 6.0.10

>>>

[brainix]

@chayim - I'd originally opened this PR here: #1448, but I made a mess of that branch. So I recreated that PR here, putting the command and the test in the right places, and keeping the methods alphabetized. How does it look now? Thanks!

[brainix]

@chayim -- I believe I've addressed your feedback. 😅 How does this PR look now?

[chayim]

Looks great @brainix. Thanks for adding lolwut support. As a total aside - I really enjoyed playing with this, I think it's very funny that this is a thing.

One last change, can you decorate the test with @skip_if_server_version_lt('5.0.0'). That's the only missing thing. Then I'll merge.

[brainix]

@chayim - Good call. I've decorated the unit test to be skipped for Redis < 5.0.0.

[chayim]

Amazing. Thanks again. Let's merge this in!