Remove /build endpoint

[aledbf]

What this PR does / why we need it:

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #4659

Special notes for your reviewer:

[k8s-ci-robot]

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[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@f0f9618). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master    #4875   +/-   ##
=========================================
  Coverage          ?   58.48%           
=========================================
  Files             ?       88           
  Lines             ?     6716           
  Branches          ?        0           
=========================================
  Hits              ?     3928           
  Misses            ?     2359           
  Partials          ?      429

Impacted Files	Coverage Δ
cmd/nginx/main.go	6.49% <ø> (ø)

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[aledbf]

/retest