Review the usage of boolean values as filter parameters

I discovered an issue while working with filters, more specifically when filtering only connectivity measures that have surface mappings. In the ConnectivityMeasureIndex table the 'has_surface_mapping' is a boolean attribute and can have values 1 or 0, but in Python the filter value is 'True' (also as a boolean). The problem I think it is that when checking the filter conditions all values are converted to strings, so "1" is not equal to "True". If I change 'True' to '1' in the Python code, then it works as expected. This is when I used SQLite, I did not test on PostgreSQL.

We should review the filters which have boolean values and make sure that they work as expected both in SQLite and PostgreSQL.