trace-cmd dump: Dump sections content

In trace file version 7, dump the content of the headers content, that
are stored as sections. Added logic to dump these headers:
 HEADER_INFO
 FTRACE_EVENTS
 EVENT_FORMATS
 KALLSYM
 PRINTK
 CMDLINES

Link: https://lore.kernel.org/linux-trace-devel/20220126095337.570867-10-tz.stoyanov@gmail.com

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>