JSR-352: Add a section in the documentation about JSR-352 integration

https://github.com/mincong-h/gsoc-hsearch/issues/122

Part 1 merged; part 2 has yet to be done:

• Extract the content from the developper guide:

  • add more detail into this user doc if there's anything useful

  • add them into each particular component's Javadoc if there's anything useful

• Add a very simple "cheat sheet", i.e. a table with a "parameter name" column, a "builder method" column, and a "description" column