[chronik] Add support for HTTPS connection to the test framework python client

Summary: This is not used in the tests but has proven to be useful when writing scripts outside of the test framework.

Test Plan:
With Chronik:

ninja check-functional

Reviewers: #bitcoin_abc, bytesofman

Reviewed By: #bitcoin_abc, bytesofman

Subscribers: bytesofman

Differential Revision: https://reviews.bitcoinabc.org/D14515