refactor ui, integrate failed jobs, load boostrap from cdn

this PR will

a) load bootstrap from a cdn
b) integrate @ruudk's failed jobs list onto the homepage
c) extract the menu into a partial
d) replace the 'listqueues' method with a 'showqueue' method (because queues are already listed on the homepage)
e) implement a poor man's pager so queues with lots of entries will, by default, show the most recent 100 entries (newest first) and show a link to display all entries (oldest first).
f) generally tidy up the html

would you mind taking a look at this please @michelsalib? sorry about the size...