WIP: evaluate anyblok compatibility version

[petrus-v]

This branch is starting point to make AWB compatible with the latest anyblok version. and ensure which dependency version are compatible and evaluate the migration effort

• first commit: freezing version likes in master
• commit 2: test the most recent lib that we can work with without any changes
• adapt unittest code using anyblok v1.0.0, sequence initialization change field name (number -> start) System.Sequence: inconsistency in 'number' field AnyBlok#45
• test anyblok version < 1.2.0
• replace nosetest by pytest and move unittest to fixture style
• adapt to anyblok>= 1.2.0 and sqla >1.4.0 following deprecation warning (discuss with the community to decide which PR should merged before starting that poin)

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TODO:

• investigate why sqlalchemy version 1.3.24 is failing
• investigate why alembic version 1.5.3 is failing