add maintainers rules and list

[gnawux]

The rules are copied from containerd project with some minor modification:

• change names
• removed subproject rules

Signed-off-by: Wang Xu gnawux@gmail.com

[gnawux]

To introduce more community contributors and maintainers, we need specify these rules. Hence we borrow the rules from the containerd project. However, I am not sure should we have a "Benevolent Dictator for Life".

Please comment here, guys.

[gnawux]

update the rules, eliminate the "Benevolent Dictator for Life". I don't like to step onto this role.

Instead, we employ simple reviewers and approvers.

Now I need one reviewer and one approver to merge it.