Python-selvpcclient

The default identity URL has been updated.

Small fix README.md:
- delete travis-ci.org (deprecated)
- add content_type for PyPI

Add skip_quotas_init in project creation

Drop support for Python < 3.8

Add filter by `user_id` for keypairs list:

selvpc keypair list -u 6f8d105aabd441a7b7a74a026a24727d

Add support for the `Cloud Quota Management API`

Requests for work with `limits` and `quotas` are sent to the `Cloud Quota Management API` instead of the `Cloud Management API`, as it was before.

Commands for working with `limits` and `quotas` have been changed. Now commands look like this:

selvpc quota set --region VALUE [--zone VALUE] --resource VALUE --value VALUE <project_id>
selvpc quota show --region VALUE <project_id>
selvpc limit show --region VALUE <project_id>