rename clientside components, add client for server communication

[eelcovdw]

Description

NOTE: sync plugin contains some changes from #397 . Merging this PR before #397 will make a small conflict in how we validate permissions in sync_action.py, for the rest they are compatible

Renames:

• client2.py -> core.py
• SyftClient -> SyftBoxRunner
  • Note: we dont use client here, because then the naming of actual clients is confusing.
• Plugins -> PluginManagerInterface
• SyftClientInterface -> SyftBoxContextInterface
• In plugins: var client is now called context

New:

• Move server API endpoints to SyftBoxClient(ClientBase)
• add to LocalSyftBox.client: SyftBoxClient and Context.client: SyftBoxClient
• different APIs are added to different namespaces in SyftBoxClient:

class SyncClient(ClientBase):
    def download(self, path: Path) -> bytes: ...

class SyftBoxClient(ClientBase):
    def __init__(self, conn: httpx.Client):
        self.conn = conn
        self.sync = SyncClient(conn)

# usage
client = SyftBoxClient.from_config(my_syftbox_config)
client.sync.download(Path("my_file"))

Affected Dependencies

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• Describe the tests that you ran to verify your changes.
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Checklist

• I have followed the Contribution Guidelines and Code of Conduct
• I have commented my code following the OpenMined Styleguide
• I have labeled this PR with the relevant Type labels
• My changes are covered by tests

[koenvanderveen]

I think in general there are two things that I have bigger questions about.

1. why does context have a client?
2. wouldnt it be better to pass a LocalSyftbox instance around instead of a context

[eelcovdw]

I think in general there are two things that I have bigger questions about.

1. why does context have a client?
2. wouldnt it be better to pass a LocalSyftbox instance around instead of a context

Discussed this in call, recap:

• The logic between Context and SyftBoxRunner is a bit double, causing some code duplication. Renamed the main syftbox class to SyftBoxRunner to make this clearer, but we might want to revisit the structures and interfaces in the future
• Context.client is just there for convenience, plugins could also manage their own client (in plugin: SyftBoxClient.from_context(ctx)). Leaving it as-is for now, can make this change in the future if we like it better