[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/cache/invalidate.go

@@ -83,6 +83,11 @@ func (c *Caches) OnInvalidateClient(client *gtsmodel.Client) {
 	c.GTS.Token.Invalidate("ClientID", client.ID)
 }
 
+func (c *Caches) OnInvalidateConversation(conversation *gtsmodel.Conversation) {
+	// Invalidate owning account's conversation list.
+	c.GTS.ConversationLastStatusIDs.Invalidate(conversation.AccountID)
+}
+
 func (c *Caches) OnInvalidateEmojiCategory(category *gtsmodel.EmojiCategory) {
 	// Invalidate any emoji in this category.
 	c.GTS.Emoji.Invalidate("CategoryID", category.ID)