instead of the generic QgsException one
Refs warning in https://github.com/qgis/QGIS/issues/55481#issuecomment-1849001802
```
/tmp/work/geography/qgis/work/qgis-3.28.13/build/python/core/build/_core/sip_corepart0.cpp:38168: warning: exception of type 'QgsProviderConnectionException' will be caught
38168 | catch (QgsProviderConnectionException &sipExceptionRef)
|
/tmp/work/geography/qgis/work/qgis-3.28.13/build/python/core/build/_core/sip_corepart0.cpp:38158: warning: by earlier handler for 'QgsException'
38158 | catch (QgsException &sipExceptionRef)
```
This is the implementation of the new DB connections API (grant proposal 2019).
Summary
The new API makes it available to QGIS core a new interface for provider connections and will allow to:
replace the provider specific QgsSettings management in QGIS4 (save/load connections from the settings) NOT IN SCOPE FOR NOW.
provide a unified API for common operations on DB connections:
executeSql and get the results
list tables names and properties and schemas
create a new vector table (no rasters for now)
create/rename/drop schemas and tables
vacuum
....
