refactoring names

To avoid confusion with the Lookup type, the three different ways of
accessing a schema have now the following names:

* page data - for revisioned struct data attached to a page
*

refactoring names

To avoid confusion with the Lookup type, the three different ways of
accessing a schema have now the following names:

* page data - for revisioned struct data attached to a page
* serial data - for an unrevisioned list of struct data attached to a
page
* global data - for an unrevisioned list of struct data not attached to
any page (formaly known as lookup schema)

The editor mechanism used for serial and global data is now called
AggregationEditor

Some reference to lookup schemas is still in the bureaucracy support
part.

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Introduce new factory methods for data access and deprecate old ones

Consolidate table access classes

Fix multi columns

Use the correct column for joining tables depending on data type. This is an initial "it works" implementation and should be revised and done more carefully.

Some fixme cleanups

Rudimentary handling of serial data

Serial data is bound to a page but does not affect versioning