Paper2remarkable

* Add support for uploading through USB (thanks to sachiniyer in 155)
* Add support for forcing source type (thanks to Barabazs in 153)
* Migrate regex url validation to validators library (thanks to Barabazs in
152)
* Update the Dockerfile (thanks to Barabazs in 150)
* Update documentation to link to rmapi fork (thanks to Barabazs in 149)
* Various fixes to broken providers and unit tests

* Add DiVA provider (thanks to koddas)
* Fix various broken providers and unit tests

* Bugfix for NeurIPS provider
* Bugfix for IACR provider
* Bugfix for PubMed provider
* Bugfix for `remarkable_dir` argument (131)
* Disable SagePub, ScienceDirect, and Taylor & Francis providers due to
CloudFlare blocking automated access
* Disable CiteSeerX due to incomplete results when fetching metadata
* Improve instructions in the readme
* Remove `cloudscraper` dependency

* Bugfix for SagePub provider
* Enable Taylor & Francis provider again

* Bugfix for ACM provider
* Fix/disable broken tests
* Disable Taylor & Francis provider

* Robustify ScienceDirect provider