[webctl] Generate static data directory on upgrade (closes #2167873) - if the folder already exists, ``upgrade`` asks for deletion, - add an option (``generate-staticdir``) to allow skipping this task. - add an option (``staticdir-path``) to specify the static data folder path. The ``gen-static-datadir`` command allows to specify the target folder but there is otherwise no way to retrieve this information during upgrade.

\.svn
^build$
^dist$
\.pyc$
\.pyo$
\.bak$
\.old$
\~$
\#.*?\#$
\.swp$
^doc/book/en/apidoc$
\.old$
syntax: regexp
.*/data/database/.*\.sqlite
.*/data/database/.*\.config
.*/data/database/tmpdb.*
.*/data/ldapdb/.*
^doc/html/
^doc/doctrees/
^doc/book/en/devweb/js_api/