refactor(core-api): do not bind directly handler to class method to allow extending response

[air1one]

Summary

Following up issue #3571 and PR #3928 which allowed to extend api response by getting the registered handler :

Refactor existing core-api routes handlers, using an arrow function to call the class method handler instead of directly binding the handler to the class method. This allow to easily extend the api response as shown in tests in PR #3928 .
(without using the arrow function, we would get issues with this when extending api response and calling the original handler)

Checklist

• Documentation (if necessary)
• Tests (if necessary)
• Ready to be merged

[codecov]

Codecov Report

Merging #4045 into develop will increase coverage by 83.21%.
The diff coverage is 84.09%.

@@             Coverage Diff              @@
##           develop    #4045       +/-   ##
============================================
+ Coverage    13.27%   96.48%   +83.21%     
============================================
  Files          715      715               
  Lines        17172    17216       +44     
  Branches      2098     2098               
============================================
+ Hits          2279    16611    +14332     
+ Misses       14785      414    -14371     
- Partials       108      191       +83     

Flag	Coverage Δ
#functional	5.98% <0.00%> (-0.02%)	⬇️
#integration	10.12% <84.09%> (+0.18%)	⬆️
#unit	94.47% <0.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
packages/core-api/src/routes/locks.ts	86.66% <50.00%> (-13.34%)	⬇️
packages/core-api/src/routes/wallets.ts	88.00% <66.66%> (-12.00%)	⬇️
packages/core-api/src/routes/delegates.ts	94.11% <80.00%> (-5.89%)	⬇️
packages/core-api/src/routes/transactions.ts	96.00% <88.88%> (-4.00%)	⬇️
packages/core-api/src/routes/blockchain.ts	100.00% <100.00%> (ø)
packages/core-api/src/routes/blocks.ts	100.00% <100.00%> (ø)
packages/core-api/src/routes/node.ts	100.00% <100.00%> (ø)
packages/core-api/src/routes/peers.ts	100.00% <100.00%> (ø)
packages/core-api/src/routes/rounds.ts	100.00% <100.00%> (ø)
packages/core-api/src/routes/votes.ts	100.00% <100.00%> (ø)
... and 642 more

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