Refactor/core cmake

[sudden6]

Working on putting Core in a separate cmake project.

• Commits follow our git commit guidelines

---

This change is 

[sudden6]

Making core an independent submodule of qTox is now complete.

Testing Audio and Video calls didn't show any regressions so far.

Since core is now independent, I think we should move unit tests that test only core functionality there too, but I want to do this in a separate PR since this one is quite big already.

[bodwok]

Reviewable status: 0 of 1 LGTMs obtained

---

src/widget/form/groupchatform.cpp, line 313 at r1 (raw file):

headWidget->updateMuteMicButton(call != nullptr, !muteState);

here checks call != nullptr, but earlier called call->setMuteMic(!muteState) and call cannot be nullptr

---

src/widget/form/groupchatform.cpp, line 322 at r1 (raw file):

headWidget->updateMuteVolButton(call != nullptr, !muteState);

same

---

src/widget/form/groupchatform.cpp, line 335 at r1 (raw file):

headWidget->updateMuteMicButton(call != nullptr, call->getMuteMic());

here call can be nullptr and when calling call->getMuteMic() will result in a segfault

---

src/widget/form/groupchatform.cpp, line 336 at r1 (raw file):

headWidget->updateMuteVolButton(call != nullptr, call->getMuteVol());

same

---

src/widget/form/groupchatform.cpp, line 342 at r1 (raw file):

(call != nullptr)

move the check call != nullptr in onMicMuteToggle() ?

---

src/widget/form/groupchatform.cpp, line 353 at r1 (raw file):

(call != nullptr)

same

[bodwok]

Reviewable status: 0 of 1 LGTMs obtained

---

src/widget/form/groupchatform.cpp, line 335 at r1 (raw file):

Previously, bodwok wrote…

headWidget->updateMuteMicButton(call != nullptr, call->getMuteMic());

here call can be nullptr and when calling call->getMuteMic() will result in a segfault

for test: start group audio call with participant, end call