deskutils/py-paperless-ngx: Fixes and improvements

• Fix NLTK configuration in paperless.conf.sample
• Mention snowball_data in NLTK instructions
• Fix sad defect that prevented rc scripts from picking up configuration data from rc.conf
• Improve startup script documentation
• Document required ACL when using a remote redis instance
• Document how to enable JBIG2 and its potential pitfalls

PR: 278424, 278425, 278426
Reported by: anonymous bugzilla user, netchild
MFH: 2024Q2