cubicweb #16121152 document transition from cubicweb-pyramid [validation pending]

there is no documentation (AFAIK) about the transition from cubicweb-pyramid, now that pyramid support has moved to CW core.

priorityminor
typetask
done in3.24.1
load left0.000
closed by#5fdc92be3ba7 [doc] Add some words in changelog about pyramid support in core + fix its title
patch[doc] Add some words in changelog about pyramid support in core + fix its title [applied]