[repository] set .eid on eschema when schema is loaded from the filesystem
enforcing the contract that a repository's schema should have .eid attribute of
entity schema set to the eid of the entity used to serialize them in the db.
Before this cset, this was not true during tests or for some c-c commands where
'quick_start' is set (eg db-restore, i18ncube...).
The change in server __init__ makes this assumption true during instance
creation: the serializing code was actually setting eid on schema object, but a
reference to a previously built schema was given instead of the one for the
latest created repository.
Closes #10450092
Templates
---------
*Templates* are specific views that do not depend on a result set. The basic
class `Template` (`cubicweb.common.view`) is derived from the class `View`.
To build a HTML page, a *main template* is used. In general, the template of
identifier `main` is the one to use (it is not used in case an error is raised or for
the login form for example). This template uses other templates in addition
to the views which depends on the content to generate the HTML page to return.
A *template* is responsible for:
1. executing RQL query of data to render if necessary
2. identifying the view to use to render data if it is not specified
3. composing the HTML page to return
You will find out more about templates in :ref:`templates`.