rename server.session.transaction into server.session.connection
The ongoing rework of the API to access the database include the splitting of
Session in two objects:
The ``Session`` object will only hold credential (user) and global session data.
A new object will publicly emerge to handle a database access. This object is
named ``Connection`` since that the way database accessors with the same property
are named in other system. So we renamed the ``Transaction`` object into
``Connection``. The ``Transaction`` object have already grown in the direction
of something directly usable by generic code, but the name ``Transaction`` is
ill suited as such object can be used for multiple database transaction in a
row.
Related to #2503918
[MESSAGES CONTROL]
disable-msg = C0301
[VARIABLES]
# Enable / disable this checker
enable-variables = yes
additional-builtins = _, display_name
[BASIC]
required-attributes=
attr-rgx = (w|[a-z_][a-z0-9_]{2,30})
variable-rgx = (w|[a-z_][a-z0-9_]{2,30})$
argument-rgx = (w|[a-z_][a-z0-9_]{2,30})$
[TYPECHECK]
generated-members=debug,info,notice,warning,error,critical,exception