Use ethersproject packages intead of ethers umbrella package

[FrederikBolding]

Using the ethersproject packages instead of the huge ethers umbrella package reduces the amount of dependencies bundled with LedgerJS. Would recommend doing this 👍

[codecov]

Codecov Report

Merging #763 (5500742) into master (6b78677) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #763      +/-   ##
==========================================
- Coverage   43.56%   43.55%   -0.02%     
==========================================
  Files          81       81              
  Lines        4823     4822       -1     
  Branches      791      791              
==========================================
- Hits         2101     2100       -1     
  Misses       2708     2708              
  Partials       14       14              

Impacted Files	Coverage Δ
packages/hw-app-eth/src/utils.ts	90.90% <100.00%> (-0.27%)	⬇️

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