Add nginx proxy_max_temp_file_size configuration option

[wayt]

What this PR does / why we need it:

This adds a configmap / annotations option to configure Nginx proxy_max_temp_file_size http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_max_temp_file_size

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

Special notes for your reviewer:

[k8s-ci-robot]

Hi @wayt. Thanks for your PR.

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[wayt]

/assign @aledbf

[wayt]

@aledbf I've been told you were refactoring the configmap/annotation option stuff, feel free to postpone that if that conflict with what you are doing 👍

[aledbf]

/ok-to-test

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@0b37598). Click here to learn what that means.
The diff coverage is 90.9%.

@@            Coverage Diff            @@
##             master    #4450   +/-   ##
=========================================
  Coverage          ?   59.32%           
=========================================
  Files             ?       87           
  Lines             ?     6721           
  Branches          ?        0           
=========================================
  Hits              ?     3987           
  Misses            ?     2298           
  Partials          ?      436

Impacted Files	Coverage Δ
internal/ingress/controller/config/config.go	98.58% <100%> (ø)
internal/ingress/controller/controller.go	47.62% <100%> (ø)
internal/ingress/annotations/proxy/main.go	59.18% <60%> (ø)

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[aledbf]

/retest

[aledbf]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aledbf, wayt

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• OWNERS [aledbf]

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[aledbf]

/retest

[aledbf]

/retest