Aof File Should be checked for writable at boot

[the123saurav]

On boot, we should check if the aof file has the required permissions, else writes to it would fail.

Repro:
Change the permissions to 444 on Linux and then start the keva server.

22:18:18.450 [main] INFO dev.keva.core.aof.AOFManager - Loading AOF file
22:18:18.461 [main] INFO dev.keva.core.aof.AOFManager - Recovered 2 commands from AOF file
22:18:18.463 [main] ERROR dev.keva.core.aof.AOFContainer - Error creating AOF file
java.io.FileNotFoundException: keva.aof (Permission denied)
at java.base/java.io.FileOutputStream.open0(Native Method)
at java.base/java.io.FileOutputStream.open(FileOutputStream.java:298)
at java.base/java.io.FileOutputStream.(FileOutputStream.java:237)
at java.base/java.io.FileOutputStream.(FileOutputStream.java:158)

[tuhuynh27]

Thanks @the123saurav, I will add the permission check at boot