Fix content language negotiation when the language negotiator "language-content-entity" is used

Problem/Motivation

The language negotiator "language-content-entity" cannot establish proper language negotiation for the content lock routes for locking and breaking entity lock.

Proposed resolution

In order for the language negotiator "language-content-entity" to be able to determine the proper content language each routes pointing to an entity should be set as as link template on the entity itself.
Additionally we should set the language option when building an URL to those routes.

Remaining tasks

User interface changes

API changes

Data model changes