Make entypo link a true URL in README

Refer to cubicweb.readthedocs.io in README docs.cubicweb.org contains outdated documentation at the moment (and for quite some time); until it gets update, refer to the up-to-date documentation on readthedocs.

[server] don't catch exception from postcommit_event() if we are in test mode The historic behavior is to hide potential exception occurring in postcommit_event(). Unfortunately logging statements are hidden by default during tests and it become very hard to debug. At least raise if we are in test mode.

[pkg] Version 3.25.0rc1

[tox] Simplify command line to build the doc

[pyramid] Drop warning about pyramid_debugtoolbar not found in debug mode Some people way want to run a pyramid server in debug mode without the toolbar. This warning is annoying for them. Others should just install and *include* the toolbar by hand.

[pkg] Add development.ini.tmpl to "cubicweb.pyramid" package data Otherwise the file is not installed and `cubicweb-ctl create -c pyramid` does not work.

[skeleton] Don't use system site packages in tox environment As we changed this in cubicweb, there is a consensus that this is not the best practice so let us change it as well for skeleton.

[doc] Update "settings" pyramid documentation Document that without "bwcompat" we can use a development.ini file directly and add a dedicated section to list configuration options.

[doc] Update the "quickstart" page of pyramid documentation Again mentioning the two modes of operations and dropping references to prior implementation.