Pass boinctui through a reverse proxy

[ptrm]

For the gotty to be accessible through port 80. I had troubles accessing the ui from public device url (AFAIR only port 80 is passed through).

Great to have a dashboard with handy stuff at hand, btw :)

[chrisys]

@ptrm another awesome contribution! Thanks 👍 send me an email to say hello at chriscw@balena.io when you get a free minute :)

[chrisys]

@balena-ci retest