[Feature] Added automatic schedule backup function

[Fan-Bob]

Automatically back up according to a schedule, such as weekly automatic backup, with a maximum backup quantity limit of 1.

[Fan-Bob]

按照计划自动备份，例如每周自动备份，最大备份数量限制为1次。

[devnoname120]

Duplicate of https://github.com/XayahSuSuSu/Android-DataBackup/issues/112