Add check_name for checks

[treydock]

Pull Request Checklist

Description

This adds check_name parameter to sensuclassic::check and check_name property to sensuclassic_check.

Related Issue

This is a continuation of #16

Motivation and Context

This allows multiple checks to be defined with same name.

[ghoneycutt]

Thanks @jovrum and @treydock

[jovrum]

I'm actually not sure if this is useful anymore. Using the following command to see check configuration:

sudo -u sensu /opt/sensu/bin/sensu-client -c /etc/sensu/config.json -d /etc/sensu/conf.d --print_config

It looks like scheduled checks must all have unique names on the client, even if they are defined in different files. I suppose this makes sense with the convention that conf.d just merges all the files in the directory together. If you define multiple checks with the same name on the same host, it looks like whichever happens to be defined last is the only one actually scheduled. If that's true, then this parameter might have been a mistake. At the very least, if there is a use case, the parameter documentation must be updated to reflect it.