K6: Deprecate and remove the current Web UI

[liclac]

To be perfectly honest, nobody uses it, it kinda sucks, and it adds a lot of build time. I'd like to replace it with something lighter weight down the line (#111), but in the shorter term, I'd like to remove it from the default build.

(It's already unavailable in Homebrew builds, because the build straight up broke there, and so far nobody has commented on it.)

[ghost]

My belief is that is should be removed completely. You should be able to visualise through InfluxDB/Grafana or through Insights. Insights has got to look good, be seperate from SaaS load injectors, persist data and be a monthly subscription. The web UI wasn't even a good idea in Locust.

[ghost]

Don't forget to remove the reference in stdout (if this is to be removed however) @robin

[olka]

Used Homebrew build and was confused by this reference to empty web page on localhost )

[StephenRadachy]

Same. This explains a lot haha.

[StephenRadachy]

Once https://github.com/loadimpact/k6/pull/337 is merged in, the last thing to do, will be to remove any looming references in the docs

[liclac]

Closed by #337