Adds WalletConnect support

[jcurbelo]

Adds WalletConnect Provider into the web3modal's wallets list

Rollup Plugins

Needed a few tweaks to get the package working:

  rollupPlugins: {
    before: [
      replace({
        'process.env.NODE_DEBUG': null,
        'process.env.WALLETLINK_URL': null,
        'process.env.WALLETLINK_VERSION': null,
      }),
      rollupCommonjs({
        transformMixedEsModules: true,
        sourceMap: true,
      }),
    ],
    after: [
      // Plugins injected after commonjs()
      nodePolyfills(),
    ]

Had to replace the default configurations of rollupCommonjs that comes with stencil.js. had to use transformMixedEsModules: true