Support for preemptive authentification

[theCapypara]

This will close #54 as it "borrows" the settings used for the Maven 2 repository for preemptive authentication. While those are made specifically for Maven 2, from looking at the code I don't see why we can't just use this logic, it is generally available for the HTTP client and works.

This pull request makes the following changes:

• It switches out the "normal" HTTP Client facet changes with a component that shows the checkbox for enabling preemptive auth.

It relates to the following issue:

• Fixes #54

This is part of an effort of me to implement better proxying support. Next up I will look into fixing #85. Once that's done and PR #100 is merged this plugin should be able to proxy all Composer 1 and Composer 2 repos.

[sonatypecla[bot]]

Thanks for the contribution! Before we can merge this, we need @theCapypara to sign the Sonatype Contributor License Agreement.

[taai]

Thanks for the contribution! Before we can merge this, we need @theCapypara to sign the Sonatype Contributor License Agreement.

Wow, really?! You are killing the will to contribute by asking to sign that "Sonatype Contributor License Agreement"! Everything is written in license "Eclipse Public License 1.0 (EPL-1.0)" already, there is no need to sign an extra agreement. And even if you want to ask contributors to sign an extra license agreement, you should mention that in README, so the potential contributors could decide should they even bother...! :unamused:

[bhamail]

My git-foo failed me. I ended up merging this via command line: See: 68b294614a4900be5a6b4fb77eb8b63f2b821f23

[bhamail]

Merged in: 68b294614a4900be5a6b4fb77eb8b63f2b821f23