remove spectra dep

backend/tracim_backend/views/frontend.py

 from tracim_backend.views import BASE_API_V2
 from tracim_backend.lib.utils.request import TracimRequest
 from tracim_backend.views.controllers import Controller
-import spectra
 
 INDEX_PAGE_NAME = 'index.mak'
 APP_FRONTEND_PATH = 'app/{minislug}.app.js'