Replace package.html with package-info.java

[SethFalco]

This converts the package.html (+ a readme.html) to package-info.java.

I noticed the package.html files but wasn't familiar with them. Learned they're basically old package-info.java files.
I was hoping to modernize that a bit, so it's more familiar, plus improves how docs are consumed in editors.

• More familiar to new developers. (I never knew package.html was a thing.)
• Preferred over package.html.

As JDK 5 arrived on the scene, package.html gave way to a new option, package-info.java, which is now preferred over package.html.
- https://www.baeldung.com/java-package-info

• package-info.java can use tags like {@link}, rather than arbitrarily naming qualified class names.

/**
 * The Default File Provider, which wraps {@link java.net.URL}.
 */
package org.apache.commons.vfs2.provider.url;

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Also fixes one typo in commons-vfs2-examples/src/main/java/org/apache/commons/vfs2/libcheck/package-info.java.

• servicde -> service

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If this is too much for one PR, feel free to close it!
I can split this up if preferred.