[feature] Conversations API (#3013)

* Implement conversations API

* Sort and page conversations by last status ID

* Appease linter

* Fix deleting conversations and statuses

* Refactor to make migrations automatic

* Lint

* Update tests post-merge

* Fixes from live-fire testing

* Linter caught a format problem

* Refactor tests, fix cache

* Negative test for non-DMs

* Run conversations advanced migration on testrig startup as well as regular server startup

* Document (lack of) side effects of API method for deleting a conversation

* Make not-found check less nested for readability

* Rename PutConversation to UpsertConversation

* Use util.Ptr instead of IIFE

* Reduce cache used by conversations

* Remove unnecessary TableExpr/ColumnExpr

* Use struct tags for both unique constraints on Conversation

* Make it clear how paging with GetDirectStatusIDsBatch should be used

* Let conversation paging skip conversations it can't render

* Use Bun NewDropTable

* Convert delete raw query to Bun

* Convert update raw query to Bun

* Convert latestConversationStatusesTempTable raw query partially to Bun

* Convert conversationStatusesTempTable raw query partially to Bun

* Rename field used to store result of MaxDirectStatusID

* Move advanced migrations to their own tiny processor

* Catch up util function name with main

* Remove json.… wrappers

* Remove redundant check

* Combine error checks

* Replace map with slice of structs

* Address processor/type converter comments

- Add context info for errors
- Extract some common processor code into shared methods
- Move conversation eligibility check ahead of populating conversation

* Add error context when dropping temp tables

internal/db/bundb/bundb.go

@@ -54,8 +54,10 @@ import (
 type DBService struct {
 	db.Account
 	db.Admin
+	db.AdvancedMigration
 	db.Application
 	db.Basic
+	db.Conversation
 	db.Domain
 	db.Emoji
 	db.HeaderFilter
@@ -158,6 +160,7 @@ func NewBunDBService(ctx context.Context, state *state.State) (db.DB, error) {
 	// https://bun.uptrace.dev/orm/many-to-many-relation/
 	for _, t := range []interface{}{
 		&gtsmodel.AccountToEmoji{},
+		&gtsmodel.ConversationToStatus{},
 		&gtsmodel.StatusToEmoji{},
 		&gtsmodel.StatusToTag{},
 		&gtsmodel.ThreadToStatus{},
@@ -181,6 +184,10 @@ func NewBunDBService(ctx context.Context, state *state.State) (db.DB, error) {
 			db:    db,
 			state: state,
 		},
+		AdvancedMigration: &advancedMigrationDB{
+			db:    db,
+			state: state,
+		},
 		Application: &applicationDB{
 			db:    db,
 			state: state,
@@ -188,6 +195,10 @@ func NewBunDBService(ctx context.Context, state *state.State) (db.DB, error) {
 		Basic: &basicDB{
 			db: db,
 		},
+		Conversation: &conversationDB{
+			db:    db,
+			state: state,
+		},
 		Domain: &domainDB{
 			db:    db,
 			state: state,