Implement background sync for xmr using flutter_daemon (#2094)

* Implement background sync for xmr using flutter_daemon

* - initialize app config in background thread
- initializeAppConfigs without loading the wallet.

* - properly do awaited calls in methodChannel
- prevent locking main thread during background sync

* add back background sync debug page
fix issues caused by xmr wallet being view only (and read only)

* changes from review
improve starting of bgsync task

* update stopBackgroundSync, await listener functions, ensure that listener always start (call _start in constructor)

* DO-NOT-MERGE: extre verbose monero logs

* stop background service when app is being opened

* improve monitoring of background sync

* update flutter_daemon to ensure network constraint
prevent throwing errors on isBackgroundSyncEnabled
check network before syncing

* Update lib/main.dart

* revert Update main.dart [skip ci]

* continously run network check

* disable charging requirement,
fix status reporting of background sync in UI

* Refactor background sync logic, and add UI notifications for battery optimization. Updated flutter_daemon version modified build.gradle for signing config to allow testing in both release and debug modes.

* verbose monero only when requested in code.
Do not start background sync when battery optimization is on

* fix background sync mode not properly reflecting state changes

* drop unnecessary dependency

---------

Co-authored-by: Omar Hatem <omarh.ismail1@gmail.com>

res/values/strings_zh.arb

@@ -69,6 +69,7 @@
   "avg_savings": "平均储蓄",
   "awaitDAppProcessing": "请等待 dApp 处理完成。",
   "awaiting_payment_confirmation": "等待付款确认",
+  "background_sync": "背景同步",
   "background_sync_mode": "后台同步模式",
   "backup": "备份",
   "backup_file": "备份文件",
@@ -922,6 +923,8 @@
   "understand": "我已知晓",
   "unlock": "开锁",
   "unmatched_currencies": "您当前钱包的货币与扫描的 QR 的货币不匹配",
+  "unrestricted_background_service": "不受限制的背景服务",
+  "unrestricted_background_service_notice": "为了启用背景同步，您需要启用无限制的背景服务",
   "unspent_change": "改变",
   "unspent_coins_details_title": "未使用代幣詳情",
   "unspent_coins_title": "未使用的硬幣",