refactor(middleware): move middleware composition code to pipeline class

[justmoon]

Composing middleware is really only done by middleware pipelines, so it should be part of the MiddlewarePipeline class, not in utils.ts.

[codecov-io]

Codecov Report

Merging #449 into master will decrease coverage by 0.68%.
The diff coverage is 88.88%.

@@            Coverage Diff             @@
##           master     #449      +/-   ##
==========================================
- Coverage   74.82%   74.13%   -0.69%     
==========================================
  Files          47       46       -1     
  Lines        2367     2177     -190     
  Branches      387      363      -24     
==========================================
- Hits         1771     1614     -157     
+ Misses        596      563      -33

Impacted Files	Coverage Δ
src/lib/utils.ts	82.6% <ø> (-1.88%)	⬇️
src/services/middleware-manager.ts	81.05% <66.66%> (-0.67%)	⬇️
src/lib/middleware-pipeline.ts	54.54% <93.33%> (+24.54%)	⬆️
src/services/admin-api.ts	38.37% <0%> (-17.77%)	⬇️
src/middlewares/balance.ts	70.17% <0%> (-4.66%)	⬇️
src/errors/invalid-json-body-error.ts	46.66% <0%> (-3.34%)	⬇️
src/controllers/ilp-prepare.ts	88.23% <0%> (-0.96%)	⬇️
src/services/accounts.ts	65.17% <0%> (-0.9%)	⬇️
src/index.ts	23.07% <0%> (ø)	⬆️
src/common/log.ts	100% <0%> (ø)	⬆️
... and 9 more

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[codecov-commenter]

Codecov Report

Merging #449 into master will decrease coverage by 0.02%.
The diff coverage is 88.88%.

@@            Coverage Diff             @@
##           master     #449      +/-   ##
==========================================
- Coverage   74.16%   74.13%   -0.03%     
==========================================
  Files          46       46              
  Lines        2175     2177       +2     
  Branches      362      363       +1     
==========================================
+ Hits         1613     1614       +1     
- Misses        562      563       +1     

Impacted Files	Coverage Δ
src/lib/utils.ts	82.60% <ø> (-1.88%)	⬇️
src/services/middleware-manager.ts	81.05% <66.66%> (-0.87%)	⬇️
src/lib/middleware-pipeline.ts	54.54% <93.33%> (+24.54%)	⬆️

---

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Δ = absolute <relative> (impact), ø = not affected, ? = missing data
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