feat: Use RepoType in Repo and impl DefaultStorage

[dariusc93]

• Implement RepoType trait in Repo
• Implement DefaultStorage to mimic previous implementation for default handling of storage
• Introduce Either and Arc implementation against the data and block store traits.
• Add set_namespace to allow one to define the namespace for indexeddb during the initialization process.
• Remove set_storage_type (will be replaced by RepoType in the future)
• Remove async-trait from BlockStore, DataStore, and PinStore, using RPiT in its place to return impl Future.

Note:

• This is a first step in reintroducing RepoType back into Repo to remove the need of dynamic dispatch when storing the storage handler in Repo, which should help to reduce allocation and footprint.
• This disables the support of custom backends for the time being as DefaultStorage is currently defined as the default backend for handling memory, file, and web (via indexeddb) storage
• Ipfs will eventually be structured as Ipfs<S: RepoType> to eventually support custom storage backends in the future, with a prelude that would use DefaultStorage