cubicweb #773448 refactor session and 'no connection' handling [resolved]

we should refactor session to have proper session objects instead of using connections as a session holder.

This should allow a better handling of session without connection as this occurs until any authentication occurs, making forgetpwd usable on site without anonymous access (that's the end goal).

prioritynormal
typeenhancement
done in3.8.0
load2.000
load left0.000
closed by<not specified>