Refactor errors to JSON and use explicit validation errors

[andrevmatos]

Part of #173

Short description
Needed so the CLI refactoring (#1636) can rely on SDK's validations, we need to have explicit error codes/messages thrown upon such validation errors.
The catched errors from API methods can be compared either by message or by code literal, like:

try {
  await raiden.getAvailability('0xinvalid');
} catch (err) {
  err.message === ErrorCodes.DTA_INVALID_ADDRESS; // by message
  err.code === 'DTA_INVALID_ADDRESS'; // literal/narrowed type, may require checking instanceof RaidenError
}

Definition of Done

• Steps to manually test the change have been documented
• Acceptance criteria are met
• Change has been manually tested by the reviewer (dApp)

Steps to manually test the change (dApp)

1. Try the approach on example, and check if it works
2. Rest of API is tested by e2e tests

[codecov]

Codecov Report

Merging #1649 into master will decrease coverage by 0.15%.
The diff coverage is 93.18%.

@@            Coverage Diff             @@
##           master    #1649      +/-   ##
==========================================
- Coverage   96.03%   95.87%   -0.16%     
==========================================
  Files         146      146              
  Lines        5246     5217      -29     
  Branches      969     1015      +46     
==========================================
- Hits         5038     5002      -36     
- Misses        157      162       +5     
- Partials       51       53       +2     

Flag	Coverage Δ
#dapp	91.73% <ø> (ø)
#sdk	97.64% <93.18%> (-0.21%)	⬇️
#sdk_integration	?

Impacted Files	Coverage Δ
raiden-ts/src/utils/types.ts	95.16% <ø> (-0.43%)	⬇️
raiden-ts/src/helpers.ts	94.01% <50.00%> (+0.05%)	⬆️
raiden-ts/src/utils/error.ts	88.88% <84.21%> (-9.80%)	⬇️
raiden-ts/src/raiden.ts	95.65% <98.11%> (-0.14%)	⬇️
raiden-ts/src/channels/utils.ts	98.14% <100.00%> (ø)
raiden-ts/src/messages/utils.ts	99.00% <100.00%> (+0.01%)	⬆️
raiden-ts/src/transfers/epics/locked.ts	98.20% <100.00%> (+<0.01%)	⬆️
raiden-ts/src/transfers/utils.ts	91.80% <100.00%> (ø)
raiden-ts/src/transport/epics/init.ts	99.04% <100.00%> (ø)
raiden-ts/src/transport/epics/presence.ts	97.64% <100.00%> (+0.02%)	⬆️
... and 4 more

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[kelsos]

Looks good on my side, but it also adds me some more work 😝
Thanks,