Move watchers out of this monorepo into their own repos

[ashwinphatak]

Now that the watcher-ts core/utils can be used as npm packages, we should move out the watchers in this monorepo into their own git repos.

• address-watcher => address-watcher-ts
• eden-watcher => eden-watcher-ts
• erc20-watcher => erc20-watcher-ts
• erc721-watcher => erc721-watcher-ts
• graph-test-watcher => graph-test-watcher-ts
• mobymask-watcher => mobymask-watcher-ts
• mobymask-v2-watcher => mobymask-v2-watcher-ts

Follow-on tasks:

• Create and publish docker images for each watcher to gitea
• Update SO stacks to use prebuilt images
• Absorb any other demo repos into SO as separate stacks and deprecate the old repos