Extend and clearify the documentation for defining solr facets.

[danceb]

I did a few doc customizations.

I ran into an issue, where the fulltext search with solr backend didn't work, as the search field within the database is defined as text but contains also numbers. In this case the passed filter looked like:

filter=[["gid","=",12345]]

instead of

filter=[["gid","=","12345"]]

I found out, that at [1] it is checked, if the field is string or not. But the documentation didn't clearify adequate, how this could be configured within the facet definition, so I added this parts and renamed the parameter accordingly.

Furthermore I spotted, that the parameter search_id_col is used in [2], so I added this within the docs.

As search_id_col and geometry_column are needed within the service, these has to be part of the SELECT query in the facet configuration, so a added these.

As the srid of the geometry is get at [3], there is no need so specify this within the SELECT query.

Last I just added to the docs an option to define the complex query within a VIEW at the database and just select the fields of this view within the facet configuration.

[1] https://github.com/qwc-services/qwc-fulltext-search-service/blob/master/src/solr_search_service.py#L188 [2] https://github.com/qwc-services/qwc-fulltext-search-service/blob/master/src/search_geom_service.py#L48 [3] https://github.com/qwc-services/qwc-fulltext-search-service/blob/master/src/search_geom_service.py#L97

[manisandro]

Thanks