(feat): Implement Email

[brrkrmn]

Summary

Tasks and new email templates according to the styles here are added to the backend

Closing #1039

Changes

• email-base.html has the common elements of the email (logos, footer)
• child templates include the dynamic content. Password reset and email verification email templates are located based on Rest Auth documentation.
• Media are uploaded to the static folder

To do

• When new badge system is implemented, badge images should be uploaded to and used from static
• Sendgrid api key and subscription settings should be added
• New design should be implemented for the comment email template

Template Previews

Account Activation Mail
New Follower Mail
Bookmark Mail

Problems with mobile clients

Gmail App on any device, Gmail on Chrome

• --Solved-- Not recognizing html symbols (copyright and emojis)
• Not rendering images --> predicted to be solved on prod

Problems with desktop clients

Outlook (2019, 2021) on Windows, OL Office 365 on Windows

• Adds black background to images in light mode
• Adds white background to images in dark mode
• Border radius is not recognized
• Image sizes are changed (max-height and object-fit not recognized)

Problems with web clients

Yahoo! Mail and AOL Mail on web

• not recognizing object-fit