Bug fixes

Changes since 8.x-1.0-alpha1:

- Rewrote routing to put items under admin/content and admin/structure
- Added first fixes for #2994174: Empty fields are being saved in ZSM Backup Date

Final bugfix for config settings form issues. Customizing the extensions is working properly. Enjoy!

Changes since release alpha6:

• #2985826 by LammensJ: Use field_parents in js settings
• #2991995 by bdlangton: element_parents in the POST url not always correct
• #2993845 by jlscott, jeremylichtman: Notice when root folder isn't set
• #2985118 by jlscott, tvdijck: Missing support for Signature Version 4

Still working on getting a beta release ready.