Add email unsubscribe UI and logic

[iamonuwa]

Description

1. Unsubscribe user from a particular email type instead of all.
2. Updated the emails to pass the email_type as part of the requests on the unsubscribe email
3. Redirect to unsubscribe email page if successful
4. Ensure that only valid email_types are processed. Others redirect to settings page

Refers/Fixes

#4465

Testing

Click on the unsubscribe link at the footer of an email from Gitcoin.

[owocki]

@danlipert i can review this if u guys want

[octavioamu]

@iamonuwa why you didn't used #4653 (comment) ? 187kb vs 51kb

[iamonuwa]

@iamonuwa why you didn't used #4653 (comment) ? 187kb vs 51kb

Exported same file from figma as jpg. But will update it with your

[codecov]

Codecov Report

Merging #5249 into master will increase coverage by 0.05%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #5249      +/-   ##
==========================================
+ Coverage   29.81%   29.87%   +0.05%     
==========================================
  Files         236      231       -5     
  Lines       19884    19133     -751     
  Branches     2838     2734     -104     
==========================================
- Hits         5929     5716     -213     
+ Misses      13711    13178     -533     
+ Partials      244      239       -5

Impacted Files	Coverage Δ
app/retail/emails.py	23.32% <0%> (+0.02%)	⬆️
app/marketing/views.py	11.38% <0%> (-0.51%)	⬇️
app/quests/models.py	44.44% <0%> (-3.31%)	⬇️
app/quests/views.py	22.77% <0%> (-2.01%)	⬇️
app/bounty_requests/forms.py	52% <0%> (-1.85%)	⬇️
app/grants/views.py	14.38% <0%> (-1.8%)	⬇️
app/economy/utils.py	83.87% <0%> (-0.98%)	⬇️
app/grants/models.py	60.88% <0%> (-0.7%)	⬇️
app/dashboard/admin.py	63.09% <0%> (-0.63%)	⬇️
app/marketing/models.py	61.72% <0%> (-0.61%)	⬇️
... and 29 more

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[iamonuwa]

@owocki any update on this one? We can chat on slack 🙈

[owocki]

jusft left a handful of comments

[owocki]

@iamonuwa did u see my comments

[owocki]

@iamonuwa bump ..

[owocki]

ok since @iamonuwa went MIA; i've taken the liberty of addressing my own comnents so this can finally go live. 9d4d963