core: api to save/get app settings to migrate them as part of the database (#3824)

* rfc: migrate app settings as part of export/import/migration

* export/import app settings

* test, fix

* chat: store app settings in db (#3834)

* chat: store app settings in db

* add combining with app-defaults

* commit schema

* test with tweaked settings

* remove unused error

---------

Co-authored-by: Evgeny Poberezkin <evgeny@poberezkin.com>

* remove app settings from export/import

* test, more settings

---------

Co-authored-by: Alexander Bondarenko <486682+dpwiz@users.noreply.github.com>

src/Simplex/Chat/Controller.hs

@@ -49,6 +49,7 @@ import Data.Word (Word16)
 import Language.Haskell.TH (Exp, Q, runIO)
 import Numeric.Natural
 import qualified Paths_simplex_chat as SC
+import Simplex.Chat.AppSettings
 import Simplex.Chat.Call
 import Simplex.Chat.Markdown (MarkdownList)
 import Simplex.Chat.Messages
@@ -245,6 +246,8 @@ data ChatCommand
   | APIExportArchive ArchiveConfig
   | ExportArchive
   | APIImportArchive ArchiveConfig
+  | APISaveAppSettings AppSettings
+  | APIGetAppSettings (Maybe AppSettings)
   | APIDeleteStorage
   | APIStorageEncryption DBEncryptionConfig
   | TestStorageEncryption DBEncryptionKey
@@ -711,6 +714,7 @@ data ChatResponse
   | CRChatError {user_ :: Maybe User, chatError :: ChatError}
   | CRChatErrors {user_ :: Maybe User, chatErrors :: [ChatError]}
   | CRArchiveImported {archiveErrors :: [ArchiveError]}
+  | CRAppSettings {appSettings :: AppSettings}
   | CRTimedAction {action :: String, durationMilliseconds :: Int64}
   deriving (Show)