cxxll::pg_query(): Extend to 14 parameters
If the RPM license header is not valid UTF-8, re-encode it

Adds column symboldb.package.normalized to the SQL schema.
Add coding style
SQL schema: Add trigram indexes on package description fields
SQL schema: Create pg_trgm extension if necessary

This is required for the tests to run.
cxxll::pg_query: Extend to 15 arguments
cxxll::rpm_package_info: Add member variable "kind"
cxxll::rpm_parser: Extract package kind and make source RPM optional
Support importing source RPMs