Hide all unnecessary fields for adding a simple blog message as adding is done usually by a site member not site manager and it was quite complex (by default blog message is submitted for approval side manager can correct errors if any).
Try to guess all possible values from parent Web Section and generate nice reference from title.
Do not manually set contributor list as this is done in a generic way by a workflow.

update script:

ALTER TABLE `catalog`
DROP INDEX `validation_state`,
DROP INDEX `simulation_state`,
DROP INDEX `causality_state`,
ADD INDEX `validation_state_portal_type` (`validation_state`, `portal_type`),
ADD INDEX `simulation_state_portal_type` (`simulation_state`, `portal_type`),
ADD INDEX `causality_state_portal_type` (`causality_state`, `portal_type`)

To update:
ALTER TABLE `stock` DROP INDEX section_uid, ADD INDEX `section_uid_portal_type` (`section_uid`, `portal_type`)

Update with:
ALTER TABLE `translation` DROP INDEX `portal_type`, ADD INDEX `type_translated_message` (`portal_type`,`translated_message`);

update with:
ALTER TABLE `inventory_stock` DROP INDEX `resource_uid`; -- exists in resource_node_uid
ALTER TABLE `stock` DROP INDEX `resource_uid`; -- exists in resource_node_uid

update with
ALTER TABLE `predicate_category` DROP INDEX `FuzzyMembership`; -- exists in Membership

update with:

ALTER TABLE `versioning` DROP INDEX `expiration_date`;
ALTER TABLE `versioning` ADD INDEX `expiration_date` (`expiration_date`);

also remove now useless related key (should have been part of former commit)

use HTMLParser instead of SGMLParser (cf. 0952bee6).

- wrong default uid was used when migrating a site that never use portal_ids
  to generate security uids
- invalidate transactional cache of security uids

This way validator scripts will be called even for empty listboxs, and this
should also remove ERP5Form/Form.py:validate_all KeyError : 'Field listbox is
not present in request object.' messages from the logs