[UI] Rename menu items

[Martouta]

Fixes THREESCALE-1459

Tasks

• Rename main menu item 'Portal' -> 'Developer Portal'
  
• Rename ‘Apps’ on dashboard (in audience section and in apis section) to ‘Applications’
  • Singular: (From the provider having only the seeds data)
    
  • Plural: (From the master having only the seeds data)
    
• Rename In the Dashboard, 'Portal' -> 'Developer Portal'

[codecov]

Codecov Report

Merging #251 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #251   +/-   ##
=======================================
  Coverage   92.59%   92.59%           
=======================================
  Files        2341     2341           
  Lines       74861    74861           
=======================================
  Hits        69315    69315           
  Misses       5546     5546

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