Use js.socialshareprivacy from pypi

Version 1.5 is now packaged from PyPI.

Developers: Remove `src/js.socialshareprivacy` subdir.
make register hint translatable
Enable logging to stdout for test suite (log level = INFO)
Added log output in case of invalid JSON configuration values
Decrease log level for memcache setup
Use equals instead of like operator in Badge.find
Add option to forbid display_name change
Added config options to map shibboleth attributes to user data

Added options:

- adhocracy.shibboleth.display_name.function
- adhocracy.shibboleth.locale.attribute
- adhocracy.shibboleth.register_form

Switched to JSON:

- adhocracy.shibboleth.userbadge_mapping
refactor shibboleth get_display_name
Shibboleth: Allow to force display_name update on login
Add display name function with random suffix
add option to force disable proxy
Don't show language territory in static page form

Addendum to e0093d02732e777d77589dfb21a33f2a1e25342b
Fix db based staticpage edit link
Fix db based staticpage submit link

Everything will be better once #676 is done.
fixup fe7fb157dd0539693ce76adda6f84c4e82f37380
Add CorsMiddleware adding a Allow-Origin=* header

This is required due to the update of js.socialshareprivacy to 1.5 which
loads JSON translation files.

See docstring in CorsMiddleware for more details.
Merge pull request #759 from nidico/feature-cors-allow-origin-all

Add CorsMiddleware adding an Allow-Origin=* header
document version pinning for new dependencies
fix register button spacing