[repo] straightforward bootstrap sequence. Closes #2841188
* kill fill_schema method which was doing to much different things, in favor of
a deserialize_method which is simply reading schema from the db and returning
it
* set_schema doesn't bother with cubes
This allows to easilly follow what's going on and so to cleanup init_cnxset_pool
to get the following boostrap order:
1. load cubes (implies loading site_cubicweb)
2. load schema
3. init data sources
4. init cnx sets
[MESSAGES CONTROL]
disable-msg = C0301
[VARIABLES]
# Enable / disable this checker
enable-variables = yes
additional-builtins = _, display_name
[BASIC]
required-attributes=
attr-rgx = (w|[a-z_][a-z0-9_]{2,30})
variable-rgx = (w|[a-z_][a-z0-9_]{2,30})$
argument-rgx = (w|[a-z_][a-z0-9_]{2,30})$
[TYPECHECK]
generated-members=debug,info,notice,warning,error,critical,exception