apps.plugin for windows

[ktsaou]

This is almost a total rewrite of the code of apps.plugin:

• [x] remove fixed allocations for struct pid_stat pointers. The previous logic was assuming that the number of possible PIDs is small. However windows supports pids up to 2 billion, so the index is now a hashtable.
• [x] reworked the sort list to have dynamic allocation for pointers.
• [x] use ARAL for allocations of struct pid_stat.
• [x] remove limitation on command name length (now it is a STRING).
• [x] new process grouping that automatically detects the top level process and groups all its sub-processes to it (process_tree grouping).
• [x] perflib moved to libnetdata
• [x] new tree grouping, which uses the top-level process of the process tree, to aggregate all the processes to. This eliminates the need to maintain app_groups.conf.
  • [x] systemd and pid 1 are already considered process orchestrators
  • [ ] user configuration is needed only for identifying other process orchestrators (e.g. containerd)
• [x] apps.plugin now maintains CPU utilization in NANOSECONDCORES, so in 1 billion increments per core.
• [x] apps.plugin now maintains memory utilization in bytes (was MiB)
• [x] apps.plugin now maintains disk I/O in bytes/sec (was KiB/sec)

On Windows, apps_groups.conf is not supported. The only possible grouping is tree.

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Tests needed:

Operating System	CPU	Memory	Disk I/O
Linux	Verified	Verified	Pending
Windows	Verified	Verified	Pending
MacOS	Pending	Pending	Pending
FreeBSD	Pending	Pending	Pending

To verify CPU, I have added a program called busy_threads, which creates N busy threads. The CPU utilization shown at the processes function and the charts, should match the number of busy threads spawn.

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:white_check_mark: ktsaou
:x: Costa Tsaousis

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