Refresh the Platform Basics section

[kito99]

Refresh is our term for rewriting/reorganizing/updating.

Please do the following:

• Add an introduction to the chapter; this should be display directly from the root nav (src/main/antora/modules/ROOT/nav.adoc). (For example, when someone clicks on the left-hand "Platform Basics" link in the navigation, the introduction should be displayed.
• Update prose/voice as per the Contributing guide.
• Remove EAR section
• Remove Glassfish-specific content
• Add a section that explains "fat" JAR packaging. Even though this isn't explicitly in the spec, it's supported by several runtimes, and many developers may only be familiar with this option.

Open issues that may need to be addressed:

Errata in packaging002 · Issue #142 · eclipse-ee4j/jakartaee-tutorial

Idea for the new term reference in the whole doc · Issue #232 · eclipse-ee4j/jakartaee-tutorial

Ambiguous using of word "resource" in the paragraph "3.1. Resource Creation". · Issue #247 · eclipse-ee4j/jakartaee-tutorial

By my opinion - it's missed one word at the end of the first sentence of the "3.1.3. Creating Resources Administratively" paragraph. · Issue #248 · eclipse-ee4j/jakartaee-tutorial

Section "Packaging Resource Adapter Archives" contains redundant and repetitive information. · Issue #254 · eclipse-ee4j/jakartaee-tutorial

Small correction in "Packaging and Deploying the hello1 Web Module" section. · Issue #256 · eclipse-ee4j/jakartaee-tutorial