asterisk: 24.0.0-rc2 image built from source with static config

Adds stub configs and noloads so a clean boot logs no ERROR lines,
ships stock indications.conf, seeds default MOH from the entrypoint.
Spec 01 synced with the real files.

Task: M0-T5

asterisk/conf/confbridge.conf

@@ -0,0 +1,20 @@
+[general]
+[default_bridge]
+type = bridge
+max_members = 20
+mixing_interval = 20
+internal_sample_rate = auto
+record_conference = no
+
+[default_user]
+type = user
+music_on_hold_when_empty = yes
+announce_user_count = yes
+announce_join_leave = no
+dsp_drop_silence = yes
+
+[default_menu]
+type = menu
+* = playback_and_continue(conf-usermenu)
+1 = toggle_mute
+#include selfphoneng/confbridge_selfphoneng.conf