Add support for multisig wallets.

[chris-namebase]

There is definitely work to be done here on the UX side but this is functional.

• Ability to create/import multisig wallet
• Support for creating a new transaction to be signed by multiple signers, signing, and broadcast

Also, probably doesn't belong in this PR but using an M1 here and had to upgrade electron-builder to get builds going.

[pinheadmz]

Ok a few big ideas:

1. refactor wallet signing proxies

This is a common pattern in wallet service:

https://github.com/kyokan/bob-wallet/blob/de90b37e9955350c58f1b92af7da38ece1ec0571/app/background/wallet/service.js#L599-L602

Basically every wallet tx action from the UI gets split into "create" and "create and sign" functions. The actual _ledgerProxy() function is going to get too bloated to start handling all these new configurations so I think a bigger refactor is necessary.

Maybe something like this:

• change _LedgerProxy() to something else like _walletProxy()
  • change in all (~26) call sites for every create tx, open, bid, reveal, atomic swap, shakedex, everything...
• _walletProxy() is new function that gets the wallet info (watch-only) and accountinfo (multisig) and then picks either the "creater" or "create-and-signer" function based on that (this way we can also add ledger to a multisig wallet)
  • the existing _ledgerProxy() function gets called from _walletProxy() if it applies
  • a new function _multisigProxy() handles the partial-signing

You can look at how _ledgerProxy() pops open the ledger modal for signing, I think a similar mechanism could work for multisig. The difference is when multisig is done, the TX won't be final or ready for broadcast yet.

2. Ledger

The Ledger app supports multisig! It's protocol is slightly different than regular key spends (you provide a redeem script not just a public key, to the device) but you can see examples: https://github.com/handshake-org/hsd-ledger/blob/s-x-compat/examples/signTransaction-p2sh.js THANK YOU @boymanjor <3

3. multisig dashboard

As discussed last week, the me-signed but un-final transactions can be stored in bobs local db and displayed in a new tab from the wallet sidebar. That way even after a restart a user can retrieve the current in-progress proposal TX and still copy it. partially signed txs could be copyable as hex or downloaded as a file that can be emailed. Any participant should be able to aggregate signatures from partially-signed txs (ie alice can collect signatures from each person and create the final tx. it doesn't necessarily have to go from alice->bob->charlie). Signautres must be placed in the witness in the correct order though, so look out for that.

In addition to editing and storing nicknames for each signer by public key, we can use some tricky wallet tricks to analyze signatures in the TX and determine who has already signed it, and display those nicknames to the user. We can add this later but I think it'd be cool to see that even in the TX history list.

[pinheadmz]

other UI nit: youll need to expand the area for receive addresses ;-)

diff --git a/app/components/ReceiveModal/receive.scss b/app/components/ReceiveModal/receive.scss
index a3316a8..ff4d760 100644
--- a/app/components/ReceiveModal/receive.scss
+++ b/app/components/ReceiveModal/receive.scss
@@ -73,7 +73,6 @@
     border: solid 1.25px rgba($black, 0.1);
     margin: 0rem 0 1.5rem 0;
     border-radius: 8px;
-    width: 350px;
     align-items: center;
     padding: 0.5rem 0.5rem 0.5rem 1rem;
   }
@@ -83,6 +82,7 @@
     font-size: 0.7rem;
     font-family: 'Roboto Mono', monospace;
     font-weight: 500;
+    margin: 5px;
   }
 
   &__disclaimer {