Add hugetop command

[eduardorittner]

The hugetop command displays system-wide hugepage informantion as well as per-process hugepage information.

It has the flags --human (for human-readable size output), --numa (to display info per numa core), --delay <N> (for display refresh) and --once (to only display once then exit). For now none of these flags are supported, and we currently only print once and then exit.

The info shown is also very minimal, but it's the same one which is displayed by the original hugetop. Since we get the info from /proc/meminfo and /sys/kernel/mm/hugepages/hugepages-<size>/... this is not portable at all and only works on linux.

[eduardorittner]

I wanted to reuse some functionality from top, specifically the header formatting with time and things, and for that I made the header module public, if you have any suggestions they are welcome.

[Krysztal112233]

I apologize for the late review of this PR. Since Debian's procps-ng does not currently include hugetop, I will continue the review later. I'm very sorry!

[Krysztal112233]

And since there were some conflicts due to the commits that were previously merged, could you please help fix them?

[Franklin-Qi]

I apologize for the late review of this PR. Since Debian's procps-ng does not currently include hugetop, I will continue the review later. I'm very sorry!

I checked and found that the hugetop command is only available in procps-ng version 4.0.5. As of now, the latest version of procps on Debian Daily is 4.0.4-9+b1.