Add Django 4.x support

Changes:

• Replace ugettext_lazy with gettext_lazy for Django 4.x support
• Remove Signal providing_args for Django 4.x support
• Replace url with re_path for Django 4.x support

CI:

• Add tox tests for Django 3.0, 3.1, 3.2, 4.0, 4.1
• Add new Python versions for Travis tests
• Bump Travis Ubuntu version for Python 3.10
• Bump Postgres (9.2 -> 11) for Django 4.0 to work

Fix incorrect JSON format

• Sell method: do not insert empty email or phone

Fix incorrect JSON format

• Sell method: do not insert empty email or phone

Support Atol protocol v4 (FFD 1.05)

• Atol API v4

Add more reties for receiving receipt report

• Change maximum retry counts for task atol_receive_receipt_report. Now its awaiting report for 29 hours.

• Changed atol_retry_created_receipts and atol_retry_initiated_receipts tasks retry period.
  Now it will retry receipts from day before yesterday