Support DBI specific schema handling

[eblondel]

Methods develop so far are essentially based on the default schema considered with the DBI connection. In many cases, as it is recommmended, users used specific schemas. Areas where code needs to be refactored include:

• software specification. Need to define a schema property (not specifically a DB connection parameter)
• handlers (entity, contact, dictionary)
  • entity_handler_dbi
  • entity_handler_dbi_df
  • entity_handler_dbi_geometry_columns
  • contact_handler_dbi
  • dictionary_handler_dbi
• entity enrichment
  • entity$enrichWithData,
  • entity$enrichSpatialCoverageFromDB
  • create_geoflow_data_from_dbi (to check)
• writeWorkflowJobDataResource
• actions
  • sf_write_generic (calling writeWorkflowJobDataResource)
  • sf_write_dbi (calling writeWorkflowJobDataResource)
  • geosapi_publish_ogc_services (for DB Postgis datastore on-the-fly creation with geosapi)

[eblondel]

This ticket targets essentially Postgres / Postgis database.
As first investigation it appears, that we could simply support the "option" arg to dbConnect to specify one or more schemas on the search path, without having to rewrite specific codes.
eg
"-c search_path=myschema" (for a single schema)
"-c search_path=hibou,public" (for multiple schemas)

This approach is particularly important as it may be needed to query two or more schemas in the same connection / geoflow.