README.md: fix indentation of cfengine_internal_agent_email

(cherry picked from commit f2197212fa8742fff571e44dd28fa212b19c7d17)
README.md: update with policy framework info

(cherry picked from commit 9db258f7fcc8b302ff9774ba8a2f35e68a9c682b)

Conflicts:
	README.md
README.md: update links

(cherry picked from commit 5bfa47d86334f8d371f45799852ab87a6425e3ca)
Disambiguate link target for select_line_matching

(cherry picked from commit b049bb810d30ed0d43d6e1ecbf5a77115c541e7f)
Explicit linking to meta and no linking to classes in this case.

(cherry picked from commit 9aee06732ea6b5630db072bb5db698610b0b1b12)