Restructure documentation

[Yauhenikapl]

Description

Update java docs.

Fixes #803

Type of change

• Updates

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works

Additional notes

[atextor]

Make sure to also update any changed xrefs to java-aspect-tooling.adoc for sections that have moved. For example in samm-cli.adoc line 200 there is xref:java-aspect-tooling.adoc#databricks-type-mapping[Databricks type mapping] which needs to be changed to xref:java-code-generation.adoc#databricks-type-mapping[Databricks type mapping]. There may be others.

[atextor]

This section should be moved to an own top-level topic (outside of the Java APIs section), because it is not Java-specific.

[atextor]

Now that we have a dedicated top-level section on Java APIs, the content of the current "Using Java Static Meta Classes" section (i.e. everything in documentation/modules/static-metaclasses) should be moved here.

1. Create a new page modules/tooling-guide/pages/java-static-meta-classes.adoc that contains the contents of modules/static-metaclasses/pages/*.adoc (in the order index, basic-usage, advanced-usage). Header levels might need to be adjusted.
2. Add page-aliases to the new .adoc to make sure that links don't break when people try to use bookmarks
3. Add a corresponding entry here in nav.adoc
4. Remove the static-metaclasses module