Add email service comparison table

[redoomed1]

Changes proposed in this PR:

• Add comparison table for the Email Services page
  - As marked on GitHub, this is a draft PR as wording and formatting is not set in stone. I'm unsure of what to rearrange, add, or remove, so any feedback is welcome. Here is a question as a starting point:
  - Table Columns: Are there any criteria that should be added to or removed from the current table?
• Alter wording about Proton and Tuta's free plans for clarity
  • https://proton.me/support/more-storage-proton-drive

    The default Proton Mail free storage is 500 MB, and you can receive an additional 500 MB [1 GB total] upon completing the Proton Mail-specific initial actions explained here.

• Update Proton Unlimited description in the "Additional Functionality" section under the Proton Mail recommendation

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[github-actions]

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[redoomed1]

Changes made before marking PR as ready for review:

• Added "Recommended Providers" second-level heading
• Added sentence referencing the detailed criteria on the page (same as the one introducing the VPN table)
• Removed space between number and unit (e.g., "500MB") to match other instances on the site
• Updated instructions for disabling Proton Mail crash reporting
• Removed pricing information for Proton Unlimited and added link to detailed support article about the paid plan instead
• Made minor grammatical changes

[jonaharagon]

changed my mind, LGTM 👍

[privacyguides-bot]

This pull request has been mentioned on Privacy Guides. There might be relevant details there:

https://discuss.privacyguides.net/t/2024-04-14/17856/1