TypeScript client SDK API follow-ups

[bfops]

• onConnect callbacks should be registered exclusively with the DbConnectionBuilder, never with the DbConnection. Similar for onDisconnect and onConnectError.
  • Relatedly, the various removeOn methods for these should not exist.
• DbConnection.wsPromise should not be exposed.
  • The DbConnection should expose a runAsync method, implemented in terms of an advanceOneMessageAsync method.
  • I don't really care if the client advances on its own if you don't call these methods, honestly, though I'd prefer if it didn't. But this should be the canonical way of "blocking" your application on the connection.
• Rename DBConnection -> DbConnection. Also rename any other DBs to Dbs.

[cloutiertyler]

• onConnect callbacks should be registered exclusively with the DbConnectionBuilder, never with the DbConnection. Similar for onDisconnect and onConnectError.
  • Relatedly, the various removeOn methods for these should not exist.
• DbConnection.wsPromise should not be exposed.
• The DbConnection should expose a runAsync method, implemented in terms of an advanceOneMessageAsync method.
  • I don't really care if the client advances on its own if you don't call these methods, honestly, though I'd prefer if it didn't. But this should be the canonical way of "blocking" your application on the connection.
• Rename DBConnection -> DbConnection. Also rename any other DBs to Dbs.

I've implemented the checkmarked ones in #135

I am going to implement the last one in a forthcoming ticket. I am not going to implement the runAsync method because I believe it's impossible to implement with the WebSocket API or at the very least I don't know how to do it. You can't poll the socket, your only choice is to register handlers. This is likely a limitation imposed by browsers. Based on the description, it seems like it could be backwards compatible and made a P2.