setenforce, {get,set}sebool, semanage-{boolean,port,permissive}: add page

[cyqsimon]

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page(s) have at most 8 examples.
• The page description(s) have links to documentation or a homepage.
• The page(s) follow the content guidelines.
• The PR title conforms to the recommended templates.
• Version of the command being documented (if known): policycoreutils-python-utils-3.6

I also updated semanage.md and getenforce.md to reference these new pages.

[spageektti]

Thank you for creating these pages. I only have one note regarding the posting of examples regarding other commands. I think it is not a good idea for the sake of clarity. Isn't it better to put this command with a description in see also?

[cyqsimon]

I included some of these foreign commands because they are likely to be used in conjunction, and there are quite a few precedences for doing this, e.g.

• apt-file
• chcon
• debootstrap
• setxkbmap
• usbip

After all the ultimate goal here is to help the user do the thing they want to do, as quickly as possible. And if that involves running a related command, I think it's justified to have it in here, especially when we have plenty of free space for it.