Improve `platforms/nodejs-ssb`

[soapdog]

Currently there is only one platform inside platforms/ and it is called ssb. This should be renamed nodejs-ssb since it implements a high-level API in terms of the ssb-server (and plugins) from the NodeJS ecosystem.

• Find all uses of direct sbot access in packages #104 - find all uses of direct sbot in packages.
• implement high-level APIs in ssb.* namespace so that that direct access is not needed.

[soapdog]

This is gonna take forever...

[soapdog]

I'm suspecting this issue is not really actionable. Of course I can work on it, but it will never come to a point where I'm totally happy with the result. The way Patchfox is built and the technical debt in this codebase prevents me from actually shipping a clean high-level API unless I rewrite all the packages.

I might close this as an interim better version and reopen if I see some breaking problem with the current codebase.

The motto of Patchfox is fail forward.