Make include related object optional

See merge request sensor-system-management/frontend!94

Merge branch 'feature-restructure-frontend-page-mixins' into 'feature-restructure-frontend-platforms'

Mixin for attachments

See merge request sensor-system-management/frontend!95

- The index variable
- Platform_type placeholder

Merge remote-tracking branch 'origin/feature-restructure-frontend' into feature-restructure-frontend-platforms

- Fix relationships names
- Enable DeviceSerializer tests

- remove old id page
- Add new platform sites

Merge branch 'feature-restructure-frontend-nbck-attachments' into 'feature-restructure-frontend-properties'

Feature restructure frontend nbck attachments

See merge request sensor-system-management/frontend!88

Merge branch 'feature-restructure-frontend-properties-nbck' into 'feature-restructure-frontend-properties'

Form for measured quantities

See merge request sensor-system-management/frontend!85

According to our discussion that the device properties are a name
that the users can't handle immediatly, we already made the
renaming to measured quantity in the device page.

The remaining notions of "property" in the configuration page
are now resolved.

Merge branch 'feature-restructure-frontend-properties' into feature-restructure-frontend-properties-nbck

And I tried to make the delete entry more consistent

Fixed usage of v-btn

See merge request sensor-system-management/frontend!86

Merge branch 'feature-restructure-frontend-properties' into feature-restructure-frontend-nbck-attachments

No redirect anymore on login

Closes #65

See merge request sensor-system-management/frontend!87

Merge branch 'feature-restructure-frontend-properties-fix-invalid-prop-warning' into 'feature-restructure-frontend-properties'

Don't show warnings for the tab values (strings allowed now)

See merge request sensor-system-management/frontend!84