Java: Promote Insecure JavaMail SSL Configuration from experimental

[atorralba]

PR to promote the Insecure JavaMail SSL Configuration query created in #3491

Changes

• Existing files were moved out of experimental
• The query was refactored to use two new libraries: frameworks/Mail.qll and. security/Mail.qll.
• Refactored tests to use InlineExpectationsTest.
• Minor changes in classes and predicates names, and in the QLDocs.

[atorralba]

@github/docs-content-codeql please review the qhelp file. Even though changes aren't introduced in this PR, it wasn't reviewed when this query was merged to experimental.

[docs-bot]

📚 Thanks for the docs ping! 🛎️ This was added to our docs first-responder project board. A team member will be along shortly to respond. To request changes to the docs you can also open a CodeQL docs issue.

[mchammer01]

@atorralba - this is looking good ✨
I've added a few comments to improve readability. I've suggested a new query description that follows our guidelines. Let me know what you think 🙂

[atorralba]

Thanks for the insight @aschackmull! I'll pay more attention to the size of predicates based on their columns in the future -- looking at the columns' uses is a good rule of thumb to see if they can be reduced, and it's definitely something to keep in mind during promotions.

I applied your suggestions and rebased to fix some conflicts.