Add api trade simulation scripts

[ghubstan]

Two regtest trading simulation scripts are contained in this change:

• trade-simulation.sh goes through the steps of creating country based F2F payment accounts for Bob & Alice, plus each step of a trade from createoffer to completion.

• limit-order-simulation.sh shows a way to trigger creation of an offer when a limit price is reached.

Each script prints CLI commands and output as they are run, providing a basic tutorial for some of the api's features.

Examples:

• trade-simulation.sh

  Simulate the entire trade protocol between Bob (taker) & Alice (maker),
  where Alice buys 0.1 BTC from Bob, paying in Renminbi (CYN).

  Note the script takes a country code (CN) not a currency code, so the
  script can create the appropriate country based face to face payment accounts.

  $ apitest/scripts/trade-simulation.sh -d buy -c cn -m 0.0 -a 0.1

• limit-order.sh

  Create a CAD/BUY 0.1 BTC order at mkt price margin of 0.0% if price falls to
  or below 47900 CAD.

  Note the script takes a country code (CA) not a currency code, so the script
  can create the appropriate country based face to face payment accounts.

  $ apitest/scripts/limit-order-simulation.sh -l 47900 -d buy -c CA -m 0.0 -a 0.1

  Create a USD/SELL 0.1 BTC order at mkt price margin of 0.0% if price rises to
  or above 37200 USD.

  $ apitest/scripts/limit-order-simulation.sh -l 37200 -d sell -c US -m 0.0 -a 0.1

Both scripts depend on functions contained in supporting bash and python3 scripts.

#5084 should be merged before this one.

[sqrrm]

Some minor changes.

I ran the scripts and I find the resulting orders strange, the price doesn't seem to correlate to the price feed, would like to understand what's happening there.

[dmos62]

These references are a bit more complicated to quote because of nested variable references. Escaping the inner quotes should do the trick: CMD_OUTPUT="$(createpaymentacct \"${CMD}\")". Readability isn't great. Alternatively, at the risk of too much vertical verbosity, you could split the inner part into a new variable: tmp="createpaymentacct $CMD".

[ghubstan]

Will you tell me why I need to make this change? It is working.
What is wrong with CMD_OUTPUT=$(createpaymentacct "${CMD}")?

[dmos62]

It's the same variable referece quoting issue I refer to in other comments. It prevents reinterpretation of some special characters, prevents word splitting. See examples here: https://tldp.org/LDP/abs/html/quotingvar.html

[sqrrm]

utACK

[sqrrm]

utACK

[ghubstan]

Force travis build (jar download problem).

[ghubstan]

Note on commit b2d8faf: This fixes a bug in the core api that was throwing the PriceRequestException exception below to the CLI when switching currencies, despite a price being available.

PriceFeedService: Exception at applyPriceToConsumer for currency CNY. priceProvider=https://price.bisq.wiz.biz/. Exception=java.lang.IllegalStateException: Stream is already completed, no further calls are allowed 
Jan-20 20:27:01.254 [BisqDaemonMain] WARN  b.c.a.CorePriceService: Exception at applyPriceToConsumer for currency CNY. priceProvider=https://price.bisq.wiz.biz/. Exception=java.lang.IllegalStateException: Stream is already completed, no further calls are allowed bisq.core.provider.price.PriceRequestException: Exception at applyPriceToConsumer for currency CNY. priceProvider=https://price.bisq.wiz.biz/. Exception=java.lang.IllegalStateException: Stream is already completed, no further calls are allowed
	at bisq.core.provider.price.PriceFeedService.applyPriceToConsumer(PriceFeedService.java:387)
	at bisq.core.provider.price.PriceFeedService.lambda$request$0(PriceFeedService.java:174)
	at bisq.core.provider.price.PriceFeedService$1.lambda$onSuccess$0(PriceFeedService.java:417)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:834)

[sqrrm]

utACK