Refractoring and add thumbnails support (without tests)

.gitignore

config/default.yaml

config/test-1.yaml

config/test-2.yaml

config/test-3.yaml

config/test-4.yaml

config/test-5.yaml

config/test-6.yaml

server.js

server/controllers/api/v1/pods.js

server/controllers/api/v1/remoteVideos.js

server/controllers/api/v1/videos.js

server/helpers/utils.js

server/initializers/constants.js

server/lib/friends.js

server/lib/requestsScheduler.js

server/lib/videos.js

server/models/videos.js

server/tests/api/multiplePods.js