Fix Ledger/Trezor transaction signing

[JamesLefrere]

This PR makes some changes to the purser-ledger and purser-trezor packages (necessitating some small changes to purser-core) such that the seeded signature values for the transaction to be signed (i.e. r, s and v) are not included. This is because ethereumjs-tx makes validations for EIP-155 that read these values (if present) and compare them with the chain ID, which was leading to validation errors for mainnet transactions.

Changes

• Remove initial r, s and v values from the unsigned transaction for Ledger and Trezor
• Add bigNumberToHexString util
• Update Ledger packages (minor version, no breaking changes)

[rdig]

Code-wise I'm all good with the changes.

But on the functional side, I don't think it works as it should.

The error I'm getting in the dApp is: insufficient funds for gas * price + value

From what I gather either the gas price or the gas value isn't passed correctly to the ledger wallet transaction:

Here's the relevant redux state:

{
  list: {
    '0sxpkzs1cdu': {
      context: 'network',
      createdAt: '2019-08-12T12:36:32.435Z',
      error: {
        type: 'SEND',
        message: 'insufficient funds for gas * price + value'
      },
      from: '0x0E07a4D6164E37e4d04d306c2e5322e268EbFEC8',
      gasLimit: '259155',
      gasPrice: '3b9aca00',
      group: {
        key: 'transaction.batch.createUser',
        id: '0sxpkzs1cdu',
        index: 0
      },
      id: '0sxpkzs1cdu',
      methodName: 'registerUserLabel',
      options: {},
      params: {
        username: 'r',
        orbitDBPath: '/orbitdb/zdpuApJ1wvTuQHFR1mpHNpavVuFnGh7XB3xcjMPg8A9aA7dmH/network.1.userProfile.0x0E07a4D6164E37e4d04d306c2e5322e268EbFEC8'
      },
      status: 'FAILED',
      loadingRelated: false
    },
    kv4ac8cy1l: {
      context: 'network',
      createdAt: '2019-08-12T12:38:19.717Z',
      error: {
        type: 'SEND',
        message: 'insufficient funds for gas * price + value'
      },
      from: '0x0E07a4D6164E37e4d04d306c2e5322e268EbFEC8',
      gasLimit: '259155',
      gasPrice: '77359400',
      group: {
        key: 'transaction.batch.createUser',
        id: 'kv4ac8cy1l',
        index: 0
      },
      id: 'kv4ac8cy1l',
      methodName: 'registerUserLabel',
      options: {},
      params: {
        username: 'r',
        orbitDBPath: '/orbitdb/zdpuApJ1wvTuQHFR1mpHNpavVuFnGh7XB3xcjMPg8A9aA7dmH/network.1.userProfile.0x0E07a4D6164E37e4d04d306c2e5322e268EbFEC8'
      },
      status: 'FAILED',
      loadingRelated: false
    },
    glau9e29esu: {
      context: 'network',
      createdAt: '2019-08-12T12:43:55.709Z',
      error: {
        type: 'SEND',
        message: 'insufficient funds for gas * price + value'
      },
      from: '0x0E07a4D6164E37e4d04d306c2e5322e268EbFEC8',
      gasLimit: '259155',
      gasPrice: '77359400',
      group: {
        key: 'transaction.batch.createUser',
        id: 'glau9e29esu',
        index: 0
      },
      id: 'glau9e29esu',
      methodName: 'registerUserLabel',
      options: {},
      params: {
        username: 'r',
        orbitDBPath: '/orbitdb/zdpuApJ1wvTuQHFR1mpHNpavVuFnGh7XB3xcjMPg8A9aA7dmH/network.1.userProfile.0x0E07a4D6164E37e4d04d306c2e5322e268EbFEC8'
      },
      status: 'FAILED',
      loadingRelated: false
    }
  }
}

Exactly the same thing happening on the Trezor side:

Note: this is not about the wallet's balance, since both my trezor and ledger have about ~0.003 ETH, which is more the enough to cover this transaction

[rdig]

I got tripped up by this too, at some point 👍

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