add link from ACCOUNT_MIGRATION doc to newer guides

Clarify PDS_EMAIL_SMTP_URL encoding requirements

Removing Duplicated Bit in installer.sh

Section on common SMTP issues

jq command needed for pdsadmin

removed duplicate request for admin email (which probably never happens anyways)

added info about configuring logging

added more info about SMTP configuration

add SMTP docs

Corrects the language for the untakedown command

Point from README directly to PDS source code

More specific link.

reset-password help command fixed

remove mention of the sandbox

Fix typos in ACCOUNT_MIGRATION.md

remove discord registration notes

Co-authored-by: Daniel Holmgren <dtholmgren@gmail.com>