refs #9178
* Add eslint deps, remove old lint deps
* Add eslint config, remove old lint configs
* Config for server and tests are different
* Tweaked rules to suit us
* Fix linting in codebase - lots of indent changes.
* Fix a real broken test
refs #8222
- differentiate between errors and fatal errors
- use gscan errors in theme middleware
- Adds a new `error()` method to `currentActiveTheme` constructor which will return the errors we receive from gscan
- In middleware, if a theme couldn't be activated because it's invalid, we'll fetch the erros and send them to our error handler. We also use a new property `hideStack` to control, if the stack (in dev mode and if available) should be shown or the gscan errors (in prod mode, or in dev if no stack error)
- In our error handler we use this conditional to send a new property `gscan` to our error theme
- In `error.hbs` we'll iterate through possible `gscan` error objects and render them.
- remove stack printing
- stack for theme developers in development mode doesn't make sense
- stack in production doesn't make sense
- the stack is usually hard to read
- if you are developer you can read the error stack on the server log
- utils.packages: transform native error into Ghost error
- use `onlyFatalErrors` for gscan format and differeniate fatal errors vo.2
- optimise bootstrap error handling
- transform theme is missing into an error
- add new translation key
- show html tags for error.hbs template: rule
closes#8056🎨 Collect together the package-related utils
- read directory actually reads a directory of packages
- parse package json is very tighly related to this
🎨 Move filterPaths -> packages.filterPackages
- this function is related to packages, not settings
- move the function to the new utils/packages
- add 100% test coverage
🎨 Simplify filterPackages code
🎨 Simplify reading of packages & themes
- This massively reduces all the complex code in the read packages & themes utils
- Added full test coverage
🎨 Improve & clarify active prop in filterPackages
- active is returned from API endpoints to combine data from multiple sources
- see https://github.com/TryGhost/Ghost/pull/8064#discussion_r103514810🎨 Better error handling
🔥 Temporarily remove custom error templates
- we will reimplement this later when we have got a better concept of loading the active theme in place
- refs #8079
