Expose ARGO_INGRESS_LINK_PROTO variable for Ingress links

[brsolomon-deloitte]

Closes #8021.

Expose ARGO_INGRESS_LINK_PROTO environment variable to explicitly
tell controller to generate links of a certain protocol for
Ingress resources.

Example:

ARGO_INGRESS_LINK_PROTO=https
ARGO_INGRESS_LINK_PROTO=http

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[brsolomon-deloitte]

Haven't written any Go in a year or so, please go easy on me 😉

[codecov]

Codecov Report

Merging #8127 (b6dd3b9) into master (3fe924e) will increase coverage by 0.00%.
The diff coverage is 70.58%.

@@           Coverage Diff           @@
##           master    #8127   +/-   ##
=======================================
  Coverage   41.51%   41.52%           
=======================================
  Files         174      174           
  Lines       22712    22714    +2     
=======================================
+ Hits         9430     9432    +2     
  Misses      11941    11941           
  Partials     1341     1341           

Impacted Files	Coverage Δ
controller/cache/info.go	66.07% <70.58%> (+0.30%)	⬆️
util/settings/settings.go	46.85% <0.00%> (ø)

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[jannfis]

Please see my comments on #8021

[brsolomon-deloitte]

Please see my comments on #8021

I'm tracking, please feel free to close this if an env var is deemed to be not the best option.