Configurable severity and SeverityLevels

[srindal]

Hi, coming from ver. 0.0.8 of your plugin I want to migrate to the react version. Besides having great features with regards to silencing alerts it also contains some changes to how severity-levels are handled with regards to sorting.

We use: info, warning, error, critical which was inspired by how the plugin worked in 0.0.8. But in 2.0 you have introduced the extra label severityValue which is a great idea, but you only map: critical, warning and info to the values: 1,2,3. Default is 4. This change makes the ordering of my severityLevels to be: critical, warning, info, error (since error is mapped to 4).

You have this PR open: #135 which suggests adding high between critical and warning. I have suggested to also have error as an option along with high.

I see too options. Either high and error both maps to severityValue 2 OR you move everything one place and have this ordering: critical, high, error, warning, info.

Either way is fine by me, but not mapping error to a severityvalue will break my sorting and make it difficult to move to ver. 2.0.

Thanks in advance.