Support time for identify service

This PR solves #203 

A new parameter "timeInstant" has been added to identify.
In the model, the property "__timeInstant__" (which is optional) determines which column to query.

At the moment only 2 layers are "time enabled" and we only need to filter returned geometries based on a year.
- ch.swisstopo.zeitreihen
   - The raster data for a year is a combination of several years.
   - Historically, in the DB we have a redundant table with several time the same geometry.
   - Between those identical rows, the only value that changes is the parameter "years"
   - In order to have a unique primary key accross this table, (which wasn't the case before today) we added a column named "bgdi_id" which is a combination of gid and years
   - For performance reasons, we had to materialized the views we were using
   - We could improve the data model by using an array of integers (we would have to change the type of lubis timeInstant column as well and transform it into an array and adapt the service accordingly).
 
- ch.swisstopo.lubis-luftbilder
  - It seems that we have duplicated primary keys among the different schemas
  - The view I am using at the moment is not complete
  - @ltclm is cleaning up the tables so that we have a consistent tables across the DB lubis.

@davidoesch We need a topic definition for Lubis.

@gjn We also need to take into account the time dimension for the result Panel withsphinx search.

@oterral We need to implement that front end as well

This PR also includes:
- An example using the parameter "timeInstant"
- 3 new tests related to "timeInstant" parameter
- Models correction and cleanup