main/bootchart2: new aport (!852)

Port bootchart2 to PostmarketOS, with three patches:
1. Modification of /etc/bootchartd.conf so that the collector
will stop after sshd has started.
2. Python 3.8 compatibility
3. Disable the interactive mode of pybootchartgui.

Use bootchart2 to profile system boot or a running system.
1. Add the bootchart2 package to your device.
2. Add the following kernel command line parameters: initcall_debug
printk.time=y quiet
3. To profile system boot
	a. add the following kernel command line parameter: PMOS_BOOTCHART2.
	This parameter causes mkinitfs to start /sbin/bootchartd instead of
	/sbin/init. /sbin/bootchartd then starts /sbin/init.
	b. (optional) modify EXIT_PROC in /etc/bootchartd.conf to define
	when the collector is to stop.
	c. Boot the system. Approximately 20 seconds after sshd starts
	(if using the default value of EXIT_PROC), the collector
	will exit.
4. To profile a running system
	a. use the command '/sbin/bootchartd start' (as root) to start
	profiling
	b. use the command '/sbin/bootchartd stop' (as root) to stop
	profiling
5. When the collector exits, /usr/bin/pybootchartgui will create
a visualization in /var/log/bootchart.png.

main/bootchart2/20-python3.8.patch

@@ -0,0 +1,41 @@
+diff --git a/pybootchartgui.py b/pybootchartgui.py
+index 947ce10..55f56ca 100755
+--- a/pybootchartgui.py
++++ b/pybootchartgui.py
+@@ -1,4 +1,4 @@
+-#!/usr/bin/python
++#!/usr/bin/python3
+ #
+ #  This file is part of pybootchartgui.
+ 
+diff --git a/pybootchartgui/parsing.py b/pybootchartgui/parsing.py
+index 993d7bf..433eb8b 100644
+--- a/pybootchartgui/parsing.py
++++ b/pybootchartgui/parsing.py
+@@ -23,7 +23,7 @@ import string
+ import re
+ import sys
+ import tarfile
+-from time import clock
++from time import perf_counter 
+ from collections import defaultdict
+ from functools import reduce
+ 
+@@ -658,7 +658,7 @@ def get_num_cpus(headers):
+ 
+ def _do_parse(writer, state, name, file):
+     writer.status("parsing '%s'" % name)
+-    t1 = clock()
++    t1 = perf_counter()
+     if name == "header":
+         state.headers = _parse_headers(file)
+     elif name == "proc_diskstats.log":
+@@ -680,7 +680,7 @@ def _do_parse(writer, state, name, file):
+         state.ps_stats = _parse_proc_ps_log(writer, file)
+     elif name == "kernel_pacct": # obsoleted by PROC_EVENTS
+         state.parent_map = _parse_pacct(writer, file)
+-    t2 = clock()
++    t2 = perf_counter()
+     writer.info("  %s seconds" % str(t2-t1))
+     return state
+