refs: TryGhost/Toolbox#147
* Replaces all references to isIgnitionError with isGhostError
* Switches use of GhostError to InternalServerError - as GhostError is no longer public
There are places where InternalServerError is not the valid error, and new errors should be added to the @tryghost/errors package to ensure that we can use semantically correct errors in those cases.
refs 829e8ed010
- i18n is used everywhere but only requires shared or external packages, therefore it's a good candidate for living in shared
- this reduces invalid requires across frontend and server, and lets us use it everywhere until we come up with a better option
- Having these as destructured from the same package is hindering refactoring now
- Events should really only ever be used server-side
- i18n should be a shared module for now so it can be used everywhere until we figure out something better
- Having them seperate also allows us to lint them properly
