Fact api changes for fact search

[timclifford]

Checklist

Main changes to api

• adds new fact search query that returns projects/environments via getProjectsByFactSearch and getEnvironmentsByFactSearch resolvers. These are available as projectsByMetadata and environmentsByFactSearch
• adds 'fact_reference' field which will allow for better fact categorisation
• adds concept of 'key' facts so we can give priority to particular facts
• updates 'knex" to v0.95

Closing issues

closes #2483

[bomoko]

I think it would be good to get @rocketeerbkw's eyes on on this too. We're adding a bit to the API and making permission changes.