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 9 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Build
passed #145847
build

00:01:07

 
  Test
passed #145849
asan

00:01:01

passed #145848
test

00:00:45

 
  Manual
manual #145854
allowed to fail manual
armv8
manual #145850
allowed to fail manual
flatpak
manual #145853
allowed to fail manual
msan
manual #145855
allowed to fail manual
ppc64le
manual #145851
allowed to fail manual
tsan
manual #145852
allowed to fail manual
ubsan
 
  Review
manual #145856
allowed to fail manual
review
manual #145857
allowed to fail manual
stop_review