Merge #2106

2106: Run e2e in parallel using jest r=bonomat a=bonomat

Once done, 
resolves #1928 
resolves #1927  (I'll create a follow-up ticket to run more tests in parallel see below. Note, running multiple tests using parity is hard because we would need a mutex around sending transaction -> nonce issue )
resolves #2137 

99% review please:

My assumption were:
* we want to get rid of our custom test runner
* we want to use jest 
* each test should have its own cnd nodes
* tests share blockchain nodes

Ticket #1927 was partially resolved. Some tests are run in parallel but not all of them. Tests within 1 tests suite (in the same file) are not run in parallel. With this setup we can't split up all blockchain based e2e tests in multiple files though. However, I have an idea how this can be resolved. I'll create a follow-up ticket on this once this PR is merged. In short we need to do this: 
1. Start blockchain nodes and store settings in a config file
2. For each test suite
  1. start a testenvironment which parses the config file and loads the settings into a global var
  2. execute tests
3. Shutdown blockchain nodes after all tests


# Open TODOs

0. [ ] re-organise blockchain tests per concern tested (happy, refund, etc) and then use it.each to loop through the assets/ledgers combinations.
The suites should probably include the protocols as those determine, which actions you can take.

1. [ ] create a follow-up ticket for parallelizing blockchain-based e2e tests: this can be quite tricky as we use 1 account for ethereum (parity-dev account) to fund each actor
3. [ ] create a follow-up ticket for renaming e2e tests: test names are currently a bit messy and don't necessarily have to contain `-` in the name. 


Co-authored-by: Philipp Hoenisch <[email protected]>
Co-authored-by: Franck Royer <[email protected]>

Author: 3 people

api_tests/.gitignore

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api_tests/.prettierignore

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