Add network config file

[dimitrovmaksim]

Resolves #837

What this PR does:

1. graph init will now also generate networks.json from the data in subgraph.yaml file in the format specified in the linked Issue.

2. graph build:

• the command now accepts two more options --network <name> and --network-file <path>
• passing the --network <name> option will update the network, address/account (NEAR uses account) and startBlock for each dataSources in subgraph.yaml to the values defined in the networks.json file. Also automatically updates all templates' (if any) network to the one passed with --network option. After that the build command will continue with the existing build functionality.
• throws an error if networks file does not exist
• throws an error if network not specified in networks file
• throws an error if a given dataSource isn't in the networks.json for the specified network.
• logs If any dataSources in the subgraph manifest are not updated
• logs If any dataSources in the configuration file are not used

Issues:
When running yarn test, jest does not exit, but if I run every test suite separately it exits correctly

Jest has detected the following 1 open handle potentially keeping Jest from exiting:

  ●  PROCESSWRAP

      at Process.emitInitNative (node:internal/async_hooks:205:43)
      at new ChildProcess (node:internal/child_process:263:18)
      at spawn (node:child_process:695:17)
      at start (node_modules/sync-rpc/lib/index.js:33:13)
      at sendMessage (node_modules/sync-rpc/lib/index.js:133:17)
      at createClient (node_modules/sync-rpc/lib/index.js:173:27)
      at Object.<anonymous> (node_modules/sync-request/lib/index.js:16:14)

[evaporei]

I just pushed a copy of your branch to trigger the CI.

I'll try to get write access to you LimeChain folks soon 🙂

Edit: it passed 🎉 , I'll try to review this between today and tomorrow 👩‍💻

[evaporei]

I'll approve and merge it for now so I don't block you further, we can do the fix of the HELP string later.

[evaporei]

I think this is missing a space before Networks file

[evaporei]

@dimitrovmaksim I just released this on 0.29.0

Soon I'll fix the Release page in Github because we have the tags but not the release notes for them (most of them are on PRs).