Only Interactive.js used it.

The JHub URL is not even exported from the Context!

Otherwise, special characters (e.g. `+`) in the idaSystemURL will be
interpreted as encoded data and converted to spaces. Which means that, say,
`git+https` will end up as `git https`. And then Bad Stuff (tm) happens.

For most services, no title is defined, so this is a no-op.

For those services where a title is defined (currently e.g. Zenodo and Rucio)
this adds the title to the navbar as a link to "/". This isn't useful — it
means that e.g. when deployed on sdc-dev these words  link to
https://sdc-dev.astron.nl/ which is a 404.