Factor out commonality between ar&ap and ar&ap&gl tables

[ehuelsmann]

The GL table has these fields:

• id integer
• reference text,
• transdate date
• notes text,
• person_id integer,
• approved boolean
• description text,
• trans_type_code character(2)

only the bold-italics fields don't exist in the AR&AP tables. Note however, that if we would name the notes field as intnotes, then all but the trans_type_code field are shared between these three tables.

The AR table has these fields:

  id integer
  invnumber text
  transdate date
  entity_id integer,
  taxincluded boolean,
  duedate date,
  invoice boolean
  shippingpoint text,
  terms smallint
  notes text,
  curr character(3),
  ordnumber text,
  person_id integer,
  till character varying(20),
  quonumber text,
  intnotes text,
  shipvia text,
  language_code character varying(6),
  ponumber text
  on_hold boolean
  reverse boolean
  approved boolean
  entity_credit_account integer
  force_closed boolean,
  description text,
  is_return boolean
  crdate date,
  setting_sequence text,     ****************
  amount_bc numeric,
  amount_tc numeric,
  netamount_bc numeric,
  netamount_tc numeric,

Note that the AP table is a subset of the AR table by exactly one field (setting_sequence).

[ehuelsmann]

The idea of the financial rewrite is that everything becomes a GL transaction and that multiple GL transactions (or maybe just journal lines) are linked to ar/ap items.