speed up startup sequence for all operations (#14148)

This speed-up is intended for faster startup times
for almost all MinIO operations. Changes here are

- Drives are not re-read for 'format.json' on a regular
  basis once read during init is remembered and refreshed
  at 5 second intervals.

- Do not do O_DIRECT tests on drives with existing 'format.json'
  only fresh setups need this check.

- Parallelize initializing erasureSets for multiple sets.

- Avoid re-reading format.json when migrating 'format.json'
  from really old V1->V2->V3

- Keep a copy of local drives for any given server in memory
  for a quick lookup.

internal/ioutil/ioutil.go

@@ -238,10 +238,7 @@ func SameFile(fi1, fi2 os.FileInfo) bool {
 	if fi1.Mode() != fi2.Mode() {
 		return false
 	}
-	if fi1.Size() != fi2.Size() {
-		return false
-	}
-	return true
+	return fi1.Size() == fi2.Size()
 }
 
 // DirectioAlignSize - DirectIO alignment needs to be 4K. Defined here as