Add distro_info task

The distro_info task will inspect /etc/redhat-release in order to
discover the distro and version.
Interesting. I was going to comment that `\d` would be more regex-ey than `0-9`, but I'm no longer so sure. Might `/etc/redhat-release` contain characters other than 0-9 due to e.g. internationalization issues?

> For Unicode (str) patterns:
>     Matches any Unicode decimal digit (that is, any character in Unicode character category [Nd]). This includes [0-9], and also many other digit characters. If the ASCII flag is used only [0-9] is matched (but the flag affects the entire regular expression, so in such cases using an explicit [0-9] may be a better choice).
> For 8-bit (bytes) patterns:
>     Matches any decimal digit; this is equivalent to [0-9].

Non-blocking comment.