[session] split session creation from default session assignation
This is the first step for more independence for Transaction.
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^build$
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^doc/book/en/apidoc$
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.*/data/database/.*\.sqlite
.*/data/database/.*\.config
.*/data/database/tmpdb.*
.*/data/ldapdb/.*
^doc/html/
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^doc/book/en/devweb/js_api/