🗃️ cdviz-db: add pre-extracted info in cdevents table

[davidB]

• add the column: subject, predicat, version, imported_at (default to CURRENT)

• add a technical PK (IDENTIY, BIG_INT, auto generated)

• add comments on every column (also missing) and table: PostgreSQL: Documentation: 16: COMMENT

  comment on table session_log is 'Our session logs';
  comment on column session_log.userid is 'The user ID';
  comment on column session_log.phonenumber is 'The phone number including the area code';

• update cdviz-collector to update those columns

• update grafana dashboard

• update documentation (of the DB ) and to create dashboard

Until first release, the migrations could be rewrite