supervisor: update to allow autorun configuration

This adds possibility to completely configure updater (autorun) trough
supervisor. Advantage of this is that supervisor is the only place that
defines uci configuration for updater (at least if we are talking about
autorun) and because of that same API can be used on top of generally
different configuration. This is handy because of back compatibility
with Turris OS 3.x and introduced cleanup in Turris OS 4.x.
7 jobs for 4.0-config-support in 9 minutes and 1 second (queued for 3 seconds)
Status Job ID Name Coverage
  Test
passed #223134
cppcheck

00:00:50

passed #223135
luacheck

00:00:54

passed #223132
system-tests

00:02:46

passed #223133
system-valgrind-tests

00:05:11

passed #223130
unit-tests

00:02:32

passed #223811
unit-valgrind-tests

00:03:49

failed #223131
unit-valgrind-tests

00:01:21