Basic auth for chartmuseum

[fmotrifork]

Chartmuseum-ui does not work with chartmuseums with basic auth enabled.

Possible implementation
If enabled, chartmuseum-ui should ask for a basic auth authentication on the main page, and use this to authenticate towards the actual chartmuseum application.

[ashuraits]

I got it working by specifying the CHART_MUSESUM_URL as
http://{username}:{password}@{chartmuseumURL}