Obtain minimumFee from mempool api in place of hardcoded value

[ghost]

Fixes #5229

example data from mempool api:

{"fastestFee":35,"halfHourFee":28,"hourFee":25,"minimumFee":6}

Bisq pricenode obtains fee info:

Feb-24 22:10:45.291 [Timer-25] INFO  b.p.m.p.MempoolFeeRateProvider$First: Retrieved estimated mining fee of 28 sat/vB and minimumFee of 12 sat/vB from mempool.space 
Feb-24 22:10:45.500 [Timer-25] INFO  b.p.m.p.MempoolFeeRateProvider$Fourth: Retrieved estimated mining fee of 27 sat/vB and minimumFee of 12 sat/vB from mempool.bisq.services 
Feb-24 22:10:46.767 [Timer-25] INFO  b.p.m.p.MempoolFeeRateProvider$Second: Retrieved estimated mining fee of 27 sat/vB and minimumFee of 12 sat/vB from mempool.emzy.de 
Feb-24 22:10:47.307 [Timer-25] INFO  b.p.m.p.MempoolFeeRateProvider$Third: Retrieved estimated mining fee of 27 sat/vB and minimumFee of 12 sat/vB from mempool.ninja 

---

averaged fee data published by PriceNode:

{
  "bitcoinFeesTs" : 1614226269,
  "dataMap" : {
    "btcTxFee" : 27,
    "btcMinTxFee" : 12
  }
}

---

Bisq app obtains fee from PriceNode:

INFO  b.core.provider.fee.FeeService: BTC tx fee: txFeePerVbyte=27 minFeePerVbyte=12 

---

Bisq withdrawal fee rate in settings screen cannot be set below the minFeePerVbyte

[wiz]

Beautiful

[ripcurlx]

@jmacxx Tests are broken right now. You need to adapt the Preferences constructor in the tests.

[ghost]

fixed, thanks @ripcurlx! 👍

[ghubstan]

I'm done with the review, but hold back on an ACK because I want to know if the old BaseCurrencyNetwork#getDefaultMinFeePerVbyte method can be removed if never to be used again. (I'm chasing these min fee rate changes in the api+tests).

[ghost]

I'm done with the review, but hold back on an ACK because I want to know if the old

Review issues have been commented on and/or resolved. 👍

[ripcurlx]

ACK - tested it on Regtest. I only get the default value set as long as it is not delivered by https://price.bisq.wiz.biz/ on regtest. Still want to wait for feedback from @wiz on the exact deployment procedure and ops state before this gets merged.

[wiz]

ACK - running PR branch on https://price.bisq.wiz.biz/getFees and new minimumFee field correctly matches 2x the minimum fee displayed on mempool.space

[ripcurlx]

Tested it and a couple of edge cases against https://price.bisq.wiz.biz/. Everything seems to behave fine. The only UX drawback is, that we are manipulating the used fee if the new min fee is above the custom set value.

[wiz]

we are manipulating the used fee if the new min fee is above the custom set value.

that's exactly what we want tho, for bisq to create valid transactions that will be accepted to the mempool, and not immediately corrupt the user's wallet heh - maybe later @jmacxx can improve the send page to have better fee display

[ripcurlx]

It is used again as soon as the minimum fee is below the custom fee again. As it prevents the problem of corrupted wallets which we see every now and then I'll create a hotfix branch based on v1.5.7.