[ADD] depend on base_field_serialized to use serialized fields

This depends on https://github.com/OCA/server-tools/pull/60. With the fixes below, I can run an odt report with the git version as of today.

[FIX] import from pyPdf
[FIX] don't pass list_class (which is browse_record_list anyway)
[FIX] don't assign to an active record's members. This causes database
writes
[FIX] remove deprecated string sizes, especially the one that is a
string itself and causes trouble in the ORM