Simplify directory structure of adoc files

src/docs/asciidoc/chapter/Java_API/01_introduction.adoc

src/docs/asciidoc/chapter/Java_API/02_architecture.adoc

src/docs/asciidoc/chapter/Java_API/03_installation.adoc

src/docs/asciidoc/chapter/Java_API/04_lowlevelapi.adoc

src/docs/asciidoc/chapter/Java_API/05_probcore.adoc

src/docs/asciidoc/chapter/Java_API/06_animation.adoc

src/docs/asciidoc/chapter/Java_API/07_evaluation.adoc

src/docs/asciidoc/chapter/Java_API/08_cosimulation.adoc

...ocs/asciidoc/chapter/Java_API/09_dependencyinjection.adoc

src/docs/asciidoc/chapter/Java_API/10_program_synthesis.adoc

src/docs/asciidoc/prob_handbook.adoc