* refactored `core/frontend/apps` to destructure common imports
* refactored `core/frontend/services/{apps, redirects, routing}` to destructure common imports
* refactored `core/frontend/services/settings` to destructure common imports
* refactored remaining `core/frontend/services` to destructure common imports
* refactored `core/server/adapters` to destructure common imports
* refactored `core/server/data/{db, exporter, schema, validation}` to destructure common imports
* refactored `core/server/data/importer` to destructure common imports
* refactored `core/server/models/{base, plugins, relations}` to destructure common imports
* refactored remaining `core/server/models` to destructure common imports
* refactored `core/server/api/canary/utils/serializers/output` to destructure common imports
* refactored remaining `core/server/api/canary/utils` to destructure common imports
* refactored remaining `core/server/api/canary` to destructure common imports
* refactored `core/server/api/shared` to destructure common imports
* refactored `core/server/api/v2/utils` to destructure common imports
* refactored remaining `core/server/api/v2` to destructure common imports
* refactored `core/frontend/meta` to destructure common imports
* fixed some tests referencing `common.errors` instead of `@tryghost/errors`
- Not all of them need to be updated; only updating the ones that are
causing failures
* fixed errors import being shadowed by local scope
refs #10438, refs #10106
* Renamed existing pages ctrl
* Splitted posts & pages for Admin API v2
* Added pages JSON input schema for Admin API v2
* Removed single author for Content & Admin API v2
- single author is not documented
- single author usage is deprecated in v0.1
- single author usage is removed in API v2
* Splitted posts & postsPublic controller for v2
* Removed requirement to send `status=all` from Admin API v2
* Removed `status` option from pages Content API v2
* Removed `status` options from Users Admin API v2
