Docs: Update ADRs

[bmtcril]

Update existing ADRs:

• Minor updates to reword "OARS" as "Aspects": fix: replaces references to OARS with Aspects in the ADRs #104
• Supersede 6. Areas of responsibility with a single tutor plugin repo instead: ADR 8. Project structure #105

Add new ADRs for:

• Protections for PII: docs: adds ADR 9. Personally Identifying Information #106
• Internationalization/localization/translations: docs: Adds ADR 10. Localization #107, docs: adds actual l10n alternative to ADR 10 #110
• Course tree data docs: Adds ADR 11. Course and block data #109
• Division of responsibilities between clickhouse and dbt: docs: adds ADR 12. Clickhouse vs dbt #112
• Don't use JSON field in clickhouse -- all useful data should be pulled out into MV fields. docs: adds ADR 13. Clickhouse experimental and beta features #113

[pomegranited]

@bmtcril I've reviewed the existing ADRs and found most of them to still be accurate, but these updates are worth doing:

• Most need minor updates to reword "OARS" as "Aspects".
• 6. Areas of responsibility references multiple tutor plugins (tutor-contrib-clickhouse, tutor-contrib-ralph, tutor-contrib-superset).
  This ADR should reflect the consolidated structure chosen for https://github.com/openedx/tutor-contrib-aspects

I think ADRs for these topics could be added:

• Protections for PII
• Internationalization/localization/translations
• Course tree data
• Division of responsibilities between clickhouse and dbt: materialized views stored in dbt: Move materialized views to dbt / squash Alembic migrations tutor-contrib-aspects#533), and collections too (soon)?
• Don't use JSON field in clickhouse -- all useful data should be pulled out into MV fields.

Do you agree? Are there any other decisions you'd like me to write up?

[bmtcril]

I think these are great, there are probably more but I'll add them as their own tasks if need be. Thanks for tackling this!

[pomegranited]

Huge thanks to you, @Ian2012 and @bmtcril , for your guidance and reviews on these PRs!
Closing this issue.