network: Move AP list population into an idle handler

The AP list needs to be updated every time APs are added or removed.
However, such addition and removal generally happens in bulk (i.e. scan
results coming in) and doing so for every AP is wasteful.

So update the widget from an idle handler instead of updating it
immediately from the signal handler.

Fixes #152
11 jobs for wip/benzea/ap-list-cpu-usage in 2 minutes and 37 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #145797
build

00:01:13

 
  Test
passed #145799
asan

00:01:23

passed #145798
test

00:01:16

 
  Manual
manual #145804
allowed to fail manual
armv8
manual #145800
allowed to fail manual
flatpak
manual #145803
allowed to fail manual
msan
manual #145805
allowed to fail manual
ppc64le
manual #145801
allowed to fail manual
tsan
manual #145802
allowed to fail manual
ubsan
 
  Review
manual #145806
allowed to fail manual
review
manual #145807
allowed to fail manual
stop_review