Add back in Cookie Domain support

[nwmac]

Env var COOKIE_DOMAIN can restrict the domain used for the session cookie.

This PR:

• Adds back in the COOKIE_DOMAIN in the Helm chart
• Adds a new helm value console.cookieDomain that overrides env.DOMAIN
• Allows this new value to be set to "-" to say not to set it (event if env.DOMAIN is set)
• Adds a view that is shown if the configured Cookie Domain does not match that of the requesting URL - since the session cookie won't work and therefore the user can not login

[cfdreddbot]

Hey nwmac!

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[codecov]

Codecov Report

Merging #2432 into v2-master will increase coverage by 0.01%.
The diff coverage is 82.14%.

@@              Coverage Diff              @@
##           v2-master    #2432      +/-   ##
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+ Coverage      71.03%   71.04%   +0.01%     
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  Files            585      586       +1     
  Lines          24536    24567      +31     
  Branches        5509     5520      +11     
=============================================
+ Hits           17429    17454      +25     
- Misses          7107     7113       +6

[irfanhabib]

LGTM, minor tweaks

[irfanhabib]

both ifs can be merged

{{- if and .Vales.console.cookieDomain (ne .Values.console.cookieDomain "-") }}

[nwmac]

@irfanhabib - The logic I want is: if cookieDomain is set, use it, unless it is set to '-' in which case do not set it, otherwise default to env.DOMAIN - I don't think what you propose will do that.

[irfanhabib]

{{end}} can be removed if the first edit is made

[irfanhabib]

Why not set this to '-'

[nwmac]

Because setting it to -would mean we don't pick up from env.DOMAIN