Fix some issues reported by lintian

Fix some issues reported by lintian

• Strip unusual field spacing from debian/control.
• Bump debhelper from old 9 to 12.
• Set debhelper-compat version in Build-Depends.
• Set upstream metadata fields: Bug-Database, Name (from ./configure).
• Drop unnecessary dependency on dh-autoreconf.
• Remove unnecessary get-orig-source-target.
• Update standards version to 4.4.1, no changes needed.

This merge proposal was created automatically by the Janitor bot (https://janitor.debian.net/lintian-fixes).

You can follow up to this merge proposal as you normally would.

Build and test logs for this branch can be found at https://janitor.debian.net/lintian-fixes/pkg/liblouis/c4e327e4-a489-4cd8-b993-d34b074cbd27.