Replace Uint8Array.from with new Uint8Array

[sisou]

• All tests pass. Demo project builds and runs.
• I have resolved any merge conflicts.

What's in this pull request?

In the voting app, we ran into an issue on iOS Safari, which threw an error of
TypedArray.from requires its this argument subclass a TypedArray constructor when trying to initialise a GenesisConfig. The stack trace traces it back to BufferUtils.fromHex().

Eventually, the issue was that an external library that was bundled with the app overwrote the browser's native Uint8Array constructor with a shim, which triggered the error in Safari.

While we will fix it in the voting app by removing this shim, we can also make the Nimiq Core library more resilient to this problem by simply not using Uint8Array.from(), but using new UintArray() instead. This PR does exactly that. It does the byte-mapping before handing it to the Uint8Array constructor, avoiding the problem.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@362d677). Click here to learn what that means.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##             master     #553   +/-   ##
=========================================
  Coverage          ?   72.91%           
=========================================
  Files             ?      206           
  Lines             ?    14094           
  Branches          ?        0           
=========================================
  Hits              ?    10276           
  Misses            ?     3818           
  Partials          ?        0           

Impacted Files	Coverage Δ
src/main/generic/utils/buffer/BufferUtils.js	88.46% <100.00%> (ø)
...ain/generic/consensus/base/primitive/Commitment.js	77.77% <0.00%> (ø)
src/main/generic/miner/MinerWorker.js	100.00% <0.00%> (ø)
...us/base/transaction/index/TransactionStoreEntry.js	100.00% <0.00%> (ø)
...in/generic/consensus/base/account/PrunedAccount.js	77.77% <0.00%> (ø)
...form/browser/network/websocket/WebSocketFactory.js	33.33% <0.00%> (ø)
src/main/generic/api/Client.js	61.73% <0.00%> (ø)
...c/main/generic/network/message/SubscribeMessage.js	92.85% <0.00%> (ø)
...in/generic/consensus/base/blockchain/BlockChain.js	54.02% <0.00%> (ø)
src/main/generic/utils/array/HashMap.js	83.33% <0.00%> (ø)
... and 197 more

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