Make deploy toolbar action work

[philippfromme]

Button exists in toolbar but doesn't work, yet.

---

We plan to improve the current deploy functionality (2.x) in the following aspects:

• Display endpoint to deploy to to user in deploy dialog
• Improve deployment error handling (Unsuccessful deployments show up as successful when deploying from modeler #838, I get a proper exception message when deploying of a diagram fails #846)
• Remember entered endpoint
• Disable shortcuts when deployment modal is active (Keyboard shortcuts still enabled while deployment modal is open #929)
• Support deployment against authenticated engines (Deployment configuration with authentication options #741)
• Change deployment strategy to deploy only changed resources (Deploy should give an option to deploy only changed resources #744)

Pulled support for more than one deployment endpoint (#804) out for now.

[barmac]

• Use log for deployment errors
• Get rid of Sorry
• Allow to provide just the root URL (without deployment/create)

[nikku]

Closed via #1063.