Read-only mode

[ntarocco]

This feature request has been created after the implementation of @max-moser

Read-only mode can be used to implement a conditional read-only mode, e.g. enabled temporarily to make system migrations smoother.

Pull requests

• Read-only mode invenio-vocabularies#231
• Read-only mode invenio-requests#293
• Read-only mode invenio-communities#830
• Read-only mode invenio-rdm-records#1120
• Introduce conditional DisableIf generator & read-only mode invenio-records-permissions#86
• Read-only mode invenio-users-resources#57
• Read-only mode invenio-drafts-resources#209