Python3 migration

[Jay07GIT]

Changes in the PR.
Removed legacy Python-2 compatibility, upgrading AWS dependencies(boto to boto 3), and introducing GitHub Actions for run tests and code coverage.

1. Removed all Python 2 compatibility code (future, future.moves.*, boto)
2. Standardized on Python ≥ 3.12

To test the PR-
Run -> tox -e check,py3

To test the github actions -
Run -> act

To test the PR with vinyldns API
To import the PR Branch use this in the requirement.txt
git+https://github.com/Jay07Git/vinyldns-python.git@python3_migration#egg=vinyldns-python

Create a new python file and use a below code to test- List zones from vinyldns

from vinyldns.zone import ListZonesResponse
from vinyldns.client import VinylDNSClient 
def main():
    print(("List Zones"))
    client = VinylDNSClient("https://vinyldns-api-url","AccessKey","SecretKey")

    zones_response = client.list_zones()
    print("Zones count:", len(zones_response.zones))
    for zone in zones_response.zones:
        print("Zone ID:", zone.id)
        print("Zone Name:", zone.name)
 
if __name__ == "__main__":
    main()