when read variable from path, read timestamp from variable and show it as humanreadble form

Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>

Moved read_timestamp to util and reads the timestamp when use -v

Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>

-w option available only when use -u with -p. otherwise throwing error message

Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>

In generating trustedcadb auth file, checked to have basicConstraints CA:TRUE
for any certificate added to trustedcadb, else returned as invalid certificate.

Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>

Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>

issue: verify with -u, -p and -w, verify of variable auth file failed
if variable not available in /sys/firmware/secvar/vars/.

fix: allowing the variable auth file verify and write
if variable not available in /sys/firmware/secvar/vars/.

Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>

Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>