Using Request.Sessions for faster and less open connections

[structwafel]

Pull Request

Related issue

Fixes #<issue_number>

What does this PR do?

• Changes all requests.get/etc methods to session.get/etc, in order to not create new connections for each request

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• [x] Does this PR fix an existing issue, or have you listed the changes applied in the PR description (and why they are needed)?
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