tools/delaytop: add interactive mode with keyboard controls

The original delaytop only supported static output with limited
interaction.  Users had to restart the tool with different command-line
options to change sorting or display modes, which disrupted continuous
monitoring and reduced productivity during performance investigations.

Adds real-time interactive controls through keyboard input:
1) Add interactive menu system with visual prompts
2) Support dynamic sorting changes without restarting
3) Enable toggle of memory verbose mode with 'M' key

The interactive mode transforms delaytop from a static monitoring tool
into a dynamic investigation platform, allowing users to adapt the view in
real-time based on observed performance patterns.

Link: https://lkml.kernel.org/r/20250907001338580EURha20BxWFmBSrUpS8D1@zte.com.cn


Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Reviewed-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>