Merge Project Modules and Dependencies Section of the docs

[asaikali]

6. Project Modules chapter is in the preface part of the docs and 22.6. Spring Security Dependencies is under the Servlet Application section. There is nothing Servlet specific about the dependencies section. I suggest merging the "Spring Security Dependencies" section into the "Project Modules" chapter and renaming "Project Modules" into "Project Modules and Dependencies"

[rwinch]

Good idea! Any chance you could submit a PR?