Change proto1 to operate over stdin

[sam-berning]

Context

It's possible with the CLI-only interface for proto1 that a settings extension command with large JSON values would exceed the max command buffer size on bottlerocket, 128KB.

In order to avoid this issue, we should change proto1 to accept input from stdin.

Definition of done

Settings extensions accept the following input mode:

echo '{"some": "json"}' | extension proto1 set