Make allow insecure host a global option

[konstin]

Not verifying the certificates of certain hosts should be supported for all kinds of HTTPS connections, so we're making it a global option, just like native tls. This fixes the remaining places using a client but were not configuring allow insecure host.

Fixes #6983 (i think) Closes #6983

[zanieb]

A couple concerning changes

[charliermarsh]

@konstin -- The current version I have here is breaking because I removed the separate setting for the uv pip interface. It seems like if a setting is global, it should by definition probably be shared between the two CLIs. What do you think? (We can just ship this with v0.5, it's fine if it's breaking.)

[konstin]

Shipping this a breaking change with 0.5 sounds fine

[konstin]

Thank you!