[dapps, playground, node] Add support for local playground testing with Ganache

[cf19drofxots]

Currently the playground only supports running against the Kovan test network.

This means local development is unnecessarily bottlenecked by the test net's throughput.

Action item: Local development should have a local test net (such as Ganache) to alleviate the mentioned problem.

[snario]

Things that come to mind:

• There is a UI element that shows if network is not Kovan; need to change that
• Ganache does not progress blocks on its own unlike Kovan, so we will need a background process which just mines blocks every couple seconds (this is called an autominer). I think ganache-cli actually has a -b flag which allows you to specify a number of seconds interval per block that you can use. Make sure this flag is only set for the Playground demo though, not for all test cases etc

[snario]

the weird part about setting up a local blockchain for the playground demo is that these addresses need to be dynamically updated

https://github.com/counterfactual/monorepo/blob/master/packages/playground-server/registry.local.json#L6-L7

[joelalejandro]

We should revisit this as part of a better development environment @snario, updating the discussion with the current stack.

[cf19drofxots]

The main issue that made this tricky to work with is when spinning up a ganache server and deploying the contracts for the dApps, there was no clean / straightforward way of injecting the dApp contract addresses into the various spots that they were getting used.

[joelalejandro]

What if we add a table to the hub DB called "dapps" that acts as a place to keep these addresses?

We could then read them through some MM command such as "counterfactual:request:contractAddresses" passing a contract name.