Improve progress reporting and general polish of installer

[Matyrobbrt]

Depends on neoforged/InstallerTools#1

[neoforged-pr-publishing]

• Publish PR to GitHub Packages

Last commit published: 0efe1d9c0c32b157dfce18d13e033f449a9613b2.

PR Publishing

The artifacts published by this PR:

• 📦 net.neoforged:legacyinstaller:3.0.13-pr-4-progress-bar

Repository Declaration

In order to use the artifacts published by the PR, add the following repository to your buildscript:

repositories {
    maven {
        name 'Maven for PR #4' // https://github.com/neoforged/LegacyInstaller/pull/4
        url 'https://prmaven.neoforged.net/LegacyInstaller/pr4'
        content {
            includeModule('net.neoforged', 'legacyinstaller')
        }
    }
}

[shartte]

Tested locally and looks good to me.