Make StrongCopyleft dependencies optional #220
Description
There are a few dependencies that exist in the code which are licensed under GPL V*.
This adds licensing complicacy, hence making it optional is the first step towards removing them.
The current list obtained via https://github.com/pilosus/pip-license-checker is
StrongCopyleft -
courlan:0.6.0 GNU General Public License v3 or later (GPLv3+) StrongCopyleft
htmldate:1.0.0 GNU General Public License v3 or later (GPLv3+) StrongCopyleft
tld:0.12.6 GNU General Public License v2 (GPLv2), GNU Lesser General Public License v2 or
later (LGPLv2+), Mozilla Public License 1.1 (MPL 1.1) StrongCopyleft
trafilatura:1.0.0 GNU General Public License v3 or later (GPLv3+) StrongCopyleft
tweet-preprocessor:0.6.0 GNU General Public License v3 (GPLv3) StrongCopyleft
zenpy:2.0.24 GNU General Public License v3 (GPLv3) StrongCopyleft
Unknown License -
bs4:0.0.1 Error Error
dnspython:1.16.0 Freeware Other
WeakCopyLeft -
certifi:2021.10.8 Mozilla Public License 2.0 (MPL 2.0) WeakCopyleft
chardet:4.0.0 GNU Library or Lesser General Public License (LGPL) WeakCopyleft
tqdm:4.62.3 MIT License, Mozilla Public License 2.0 (MPL 2.0) WeakCopyleft