Move all file opreation on IO thread.

[MohitMaliFtechiz]

Describe the bug
We have the FileExtension class. In this class, we perform file operations, e.g., exit (), freeSpace, and totalSpace etc. However, we are using the runBlocking method, which uses the mainThread. Due to this, performing these actions on large files can lead to a crash, just like #4031. However, for #4031 there are 4-5 crashes but the application should not crash.

It is a very big change for our application since we are using these file extensions in our whole project, and after purely moving these to the IO thread we have to handle the UI to reflect the file operation changes.

Expected behavior
All the file operations should be performed on the IO thread without affecting the existing functionality.

Environment

• Version of Kiwix Android: 3.11.1