use https for api_service_url by default #17924

Description:

Use https for the api_service_url by default.
Fixes #8235

Review

• [ ] Functional review done
• [ ] Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• [ ] Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• [ ] Security review done
• [ ] Wording review done
• [ ] Code review done
• [ ] Tests were added if useful/possible
• [ ] Reviewed for breaking changes
• [ ] Developer changelog updated if needed
• [ ] Documentation added if needed
• [ ] Existing documentation updated if needed

This issue is in "needs review" but there has been no activity for 7 days. ping @matomo-org/core-reviewers

@codegain I'll close this PR for now as we have discussed internally a slightly more complicated approach where we'll first add a system check to prepare that HTTPS will be enforced eventually and people can fix it and also add a setting to disable HTTPS if they can't get HTTPS to work etc. We very appreciate that you created this PR and it started a discussion on how to get there without compromising security and without regressing too much at the same time etc. Thanks for this.