Update debian files: set maintainer, update copyright and control

Update debian/control, debian/copyright, and debian/changelog files.

• Set new maintainer in debian/control: Osman Romulo Condori Guevara.
• Add Rules-Requires-Root: no in debian/control.
• Update Standards-Version to 4.7.2 in debian/control (no changes needed).
• Replace pkg-config with pkgconf in Build-Depends in debian/control.
• Fix and update license information in debian/copyright:
  • Add Upstream-Contact field.
  • Move and clarify Special license text for src/pcre2_cpp_wrapper.h.
  • Update year range for Mo Zhou.
• Add changelog entry to debian/changelog, closing ITA bug #1098915.