Add syntax coloring for editing rules

[thomasdarimont]

Problem description

No syntax highlighting for rule editing.

Steps to reproduce the problem

1. Edit a pipeline rule

Environment

• Graylog Version: 2.2.1-1 (DockerHub Image)
• Pipeline Processor plugin version: 2.2.1-1

FYI The (currently) latest version of brace (0.9.1) supports a drools highlighter.

[joschi]

@thomasdarimont FYI, the syntax used in this plugin is not identical to the Drools syntax.

[thomasdarimont]

Oh sorry - didn't pay enough attention. Was confused by the stream rules and
already wondered about the custom grammar in the plugin... the graylog rabbit hole is pretty deep :)

I change the title to just syntax coloring then.

[thomasdarimont]

I build small custom ace editor configuration that highlights the graylog rulelang source quite nicely.

If you'd like to give it a try have a look at this gist

I'm now trying to figure out how to built this in.