[global] Changed raw "header('Location:') to Friendica's System::externalRedirect()

[Quix0r]

Changes:

• rewrote header('Location: foo'); to System::externalRedirect()
• changed double-quotes to single
• no executable permission on these files

Fixed an issue reported in https://github.com/friendica/friendica/issues/11632#issuecomment-1237755268

[Quix0r]

This change requires https://github.com/friendica/friendica/pull/11900 to be merged or else this won't add those headers.