HowToCreateAService.txt: remove broken links.
Properties.txt: remove broken links.
SecuritySystem.txt: remove broken links.
merge develop -D org -I include -E exclude: PR 369 (Cpp: Correct content and markup)
merge develop -D org -I include -E exclude: PR 445 (Homebrew and Python (rebased onto develop))
merge develop -D org -I include -E exclude: PR 447 (Fix doc links to removed client component (see #11390) (rebased onto develop))