Merge pull request #11094 from zfgrnzfsberire/dependencies-as-submodules

add submodules: bbb-webrtc-sfu, etherpad-lite, freeswitch

.gitmodules

+[submodule "bbb-webrtc-sfu"]
+	path = bbb-webrtc-sfu
+	url = https://github.com/bigbluebutton/bbb-webrtc-sfu
+[submodule "etherpad-lite"]
+	path = etherpad-lite
+	url = https://github.com/bigbluebutton/etherpad-lite
+[submodule "freeswitch"]
+	path = freeswitch
+	url = https://github.com/signalwire/freeswitch

bbb-webrtc-sfu @ a73429eb

+Subproject commit a73429ebb82827a6be9cfae7b22f154a47d4dcf4

etherpad-lite @ 2dbc25b9

+Subproject commit 2dbc25b90a5ea164458762154c7954cd04dadffc

freeswitch @ 133fc2c8

+Subproject commit 133fc2c870050fc7edbf79dbedec74c34f2cbfe7