feat: add Skip TLS Verify toggle to datasource config

[OVR92]

Adds a frontend toggle and backend support for skipping TLS certificate verification.

[NeedleInAJayStack]

Hey @OVR92, this is great! I had considered in the past building out better HTTP client configuration, and this is a great place to start.

After a quick review, I did notice that this would be a lot simpler if the underlying haystack package allowed passing an http.Client directly, so I added that in this PR. I then combined that with your work here to create #49. Just in the interest of simplicity and communication, I think we'll go with that PR and I'll close this one.

Thanks for coming up with this idea and contributing! Hope you're finding value in this package!

[OVR92]

Sounds good, and thank you for all your work on this! We use it every day for dashboards to monitor performance and track utilities across our campus, but we hit a bit of a snag when our SkySpark SSL certificate accidentally lapsed. I enlisted the help of Claude to get us through while our IT team worked on fixing the certificate, so I can't really take credit for any of this. I'm glad that some of it might make its way into the official repo and potentially help others who end up in a similar situation.

Thanks again!

[NeedleInAJayStack]

You're welcome! That's awesome that this plugin has been helpful to you! Surprisingly, I don't have a ton of insight into who is using this or at what scale, so it's really cool to hear from users.

I'm just working through the plugin update process with Grafana, but I'll post back with a version number once it's approved.

[NeedleInAJayStack]

This feature has been released in version 0.0.28