[Improvement] Migrate html2pdf to weasyprint

[nikitaermishin]

PR for improvement commit, which makes a migration from html2pdf to weasyprint. Changes:

• Adds weasyprint>=44 to requirements.txt instead of xmtml2pdf
• Changes STATIC_URL in tests/settings.py to compatible with weasyprint
• Creates BATCH_PDF_TEMPLATE_BASE_URL in django_freeradius/settings.py
• Changes generate_pdf function in django_freeradius/utils.py, now it works using weasyprint API

Closes #243

[nikitaermishin]

@nemesisdesign The problem is about providing base_url to HTML function. base_url should provide absolute path to the folder, which contains our css and js files. I suppose we could do it by some better way (including fix of STATIC_URL value mistake). So I can compose BATCH_PDF_TEMPLATE_BASE_URL of absolute way to django_freeradius folder and STATIC_URL variable. Will provide commit soon, so you will have opportunity to understand what I am talking about. :smiley:

[nikitaermishin]

I think this weasyprint>=43,<=44 should be weasyprint>=44,<45

@2stacks It has no other versions between 44 and 45, so isn't that the same as weasyprint==44? If so, could I use any of them?

[2stacks]

I think this weasyprint>=43,<=44 should be weasyprint>=44,<45

@2stacks It has no other versions between 44 and 45, so isn't that the same as weasyprint==44? If so, could I use any of them?

Yes, they all achieve the same thing. However, if you look at the current file, my RFC is purely based on consistency. At some point 44 will be the supported lower bound and some future 4x will be the upper bound.

[nikitaermishin]

@nemesisdesign Ok, rebased my branch. Now working on the problem :smiley:

[coveralls]

Coverage remained the same at 99.927% when pulling 8e1d7de1bc89dc5e75fcfdd6c34fb4ee93c9c8d3 on nikitaermishin:migrate_to_weasyprint into c8587d64e42bc5675d026e4409c3599413366cfd on openwisp:master.

[nemesifier]

PS: please also rebase on the current master.