Just update to the new repo path "github.com/signalapp"

Closes #7469

.github/ISSUE_TEMPLATE.md

@@ -11,7 +11,7 @@ Let's begin with a checklist: replace the empty checkboxes [ ] below with checke
 
 I have:
 - [ ] searched open and closed issues for duplicates
-- [ ] read https://github.com/WhisperSystems/Signal-Android/wiki/Submitting-useful-bug-reports
+- [ ] read https://github.com/signalapp/Signal-Android/wiki/Submitting-useful-bug-reports
 
 ----------------------------------------
 

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,12 +1,12 @@
 <!-- You can remove this first section if you have contributed before -->
 ### First time contributor checklist
 <!-- replace the empty checkboxes [ ] below with checked ones [x] accordingly -->
-- [ ] I have read [how to contribute](https://github.com/WhisperSystems/Signal-Android/blob/master/CONTRIBUTING.md) to this project
+- [ ] I have read [how to contribute](https://github.com/signalapp/Signal-Android/blob/master/CONTRIBUTING.md) to this project
 - [ ] I have signed the [Contributor License Agreement](https://whispersystems.org/cla/)
 
 ### Contributor checklist
 <!-- replace the empty checkboxes [ ] below with checked ones [x] accordingly -->
-- [ ] I am following the [Code Style Guidelines](https://github.com/WhisperSystems/Signal-Android/wiki/Code-Style-Guidelines)
+- [ ] I am following the [Code Style Guidelines](https://github.com/signalapp/Signal-Android/wiki/Code-Style-Guidelines)
 - [ ] I have tested my contribution on these devices:
  * Device A, Android X.Y.Z
  * Device B, Android Z.Y