refs https://github.com/TryGhost/DevOps/issues/45
- this switches the monorepo over to using Nx instead of Lerna, because
we don't currently need the versioning+publishing capabilities
- this also adds an `nx.json`, which allows us to enable task caching
- also adds `build:ts` to the TS projects, which is cached for fast execution
- how these interact with the dev.js script will hopefully soon be
reworked to be a better experience
This is an initial start to using TypeScript in our non-core Ghost packages.
- Adds a prepare script to build the project after installing deps
- Adds an initial tsconfig.json which is compatible with our node env
- Migrates all of the code to TypeScript, including tests
- Updates tests to use ts-node so that we don't need to compile the tests
- ts-node is installed at the top level because the env is weird with lerna and
doesn't work otherwise
- Updates the yarn dev script to build the project with the --all and --revisions flag
This package will be used to contain the logic for determining when a
revisions should be generated for a post. It will be used by the Post
model during saving and will not handle the storage of revisions
