Small errors and unused code in displayer
Remove unused CSS
Move sheet and user-picker styles to app.scss

This is in preparation for adding these things to the site pages.
Make `layout.inline_webfont` a property

This is simpler than having to set this manual on the layout and we
only deliver it separately when Content Security Policy is active.
Therefore, it makes sense to make it a property that depends on
`layout.csp`.
Move base_url to renderer globals
Move <base> and <link rel="service"> to base.pt
Set the service_url in a subscriber

And remove the unused token_url value from the app rendering.
Don't accumulate entity URIs on aliased searches

Search each one individually. This was always the intent but the code
was wrong.
whitespace
Update some ES notes in the INSTALL docs
Better messages in ./bootstrap

Thanks to @onceuponatimeforever for making it clear that the messages
emitted by the bootstrap script could be much better.

The new messages take care to reassure the developer that optional
dependencies are optional. Required dependencies cause the script to
error out early with status code 1 and now instruct the developer to
consult the installation documentation.

Close #1176