Implement a single validation function around the service_uri

[ahmedsobeh]

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Description of change

Created url_parser and removed duplication of parse_url. This PR resolves issue #25

I created a url_parser module and added it to the parsers folder. I then used this module in both connection modules (the normal one and the asyncio one) and updated the tests accordingly.

[aiven-sal]

LGTM
I squashed and rebased some commits and will merge as soon as the CI completes