Explain 'Delete Account'

[david-allison]

• Invalid account/data deletion link listed in Google Play Store data safety form Anki-Android#16256
• feat: initial 'Remove account' implementation Anki-Android#16260

[mikehardy]

just cross-linking with the new specific account removal landing page we have referenced in our Play Store data area

• feat: add AnkiDroid-specific page for AnkiWeb account removal #140

https://ankidroid.org/remove-account.html