Updated top bar implementations

[lhuijser]

Changes:

• Matched styling of top bars to the colour scheme
• Split top bar into two - one for the dashboard, one for within specific road trips
• Added attendee list modal for the road trip top bar (ability to add new attendee to roadie only shows if the user is an organiser)
• Return to dashboard from within a roadie by clicking on home icon
• Road trip top bar title now equals the name of the roadie the user is in

Images: Roadie specific top bar:

Dashboard top bar:

Attendee modal:

Closes #33 Closes #37 Closes #32