Improve web editor

* focus on web editor
* Make editor looks same for new and edit file
* Refactor editor JS
* Improved satellite logic for new files

See merge request !1441

File creation and editing refactored

* Refactored controllers/helpers/views related to blob resource
* make it possible to create new file in empty repository

Second step in building #1930

See merge request !1440

Bigger font-size for code browsing

See merge request !1439

Create first file from empty repository via UI. pt1

* Backend can now commit file to empty repository.
* Empty project UI has new file button

First step in building #1930

See merge request !1438

Redesign project avatar page

See merge request !1437

Notify participants on close or reopen of issue/mr

Fixes #1891

cc @sytse

See merge request !1436

Also refactor NotificationService a bit

Improve project icon UI

See merge request !1435

Remove default project icon

See merge request !1434

Project avatar

See merge request !1433

Add return value example to ssh key creation

See merge request !307