adding `ttl` as a first class check attribute to lwrp

[majormoses]

Signed-off-by: Ben Abrams me@benabrams.it

Description

Add first class support for TTL checks rather than specifying it in additional.

Misc Changes:

• sort the list of sensu_check attributes
• add list of attributes to the README

Motivation and Context

Check TTLs are often used in conjunction with proxy (formerly JIT) client checks. This allows you to know when your proxy client has stopped reporting in.

sensu doc: https://docs.sensu.io/sensu-core/1.3/reference/checks/#check-attributes

How Has This Been Tested?

Added to existing proxy check as that is where it is most commonly used.

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have read the CONTRIBUTING document.

[majormoses]

released: https://supermarket.chef.io/cookbooks/sensu/versions/4.4.0