UI: Search field with syntax coloring and autocompletion

[psrok1]

Your checklist for this pull request

• I've read the contributing guideline.
• I've tested my changes by building and running the project, and testing changed functionality (if applicable)
• I've added automated tests for my change (if applicable, optional)
• I've updated documentation to reflect my change (if applicable)

What is the current behaviour?

MWDB search syntax is pretty verbose and complex and may be intimidating for unexperienced users. It would be nice to have at least syntax coloring and autocompletion suggestions to make the malware database more discoverable.

What is the new behaviour?

This PR introduces basic syntax coloring. It's based on two components:

• Moo-based lexer, specialized for MWDB-specific Lucene syntax
• Slate-based input component that uses contenteditable div for rich rendering

Second thing added by this PR is autosuggestion mechanism. Search query can be easily typed using keyboard:

I have also implemented attribute suggestions, including subfields. Information about subfields is fetched from "Example value" - part of Rich attributes template.

Right now the autosuggestion feature is a bit limited:

• it supports only field suggestion
• suggestion applies only to the end of query string, it can't provide suggestion for something typed in the middle of the query