UI styling

[lpissinali]

• Adding search fields to unavailable and registered screens #16
• Styling modals
• Converting input fields to static text on registering new ens name #7
• Adding terms page (missing styling) #2

[jeluard]

@lpissinali Could you link any relevant issues being fixed / addressed ?

[bgits]

added a fix for: https://github.com/status-im/ens-usernames/issues/31