Add scripts and configuration files for mergerfs setup and testing

- Created backup files for wipefs on specific disk partitions.
- Added db-test script to verify metadata.db file integrity.
- Documented successful mergerfs branch and pool configurations in mfs-good.txt.
- Implemented mfs write test in mfs-test.txt.
- Included mergerfs version and device information in mfs.txt.
- Developed rebuild scripts for mergerfs stages, including verification and filesystem creation.
- Generated stage logs for each rebuild step to track disk and filesystem status.
- Added checks for systemd mount requirements and filesystem verification in stage4.

others/plex-lvm-recovery/lvs-segments.txt

@@ -0,0 +1,6 @@
+  LV       Start   SSize  Type   Devices          
+  plex-new      0  <7.28t linear /dev/sdb(0)      
+  plex-new  <7.28t <5.46t linear /dev/sdc(0)      
+  plex-new <12.74t <3.64t linear [unknown](0)     
+  plex-new  16.37t <5.46t linear /dev/sdd(0)      
+  plex-new  21.83t <1.82t linear /dev/sdc(1430791)