XWIKI-11632: Only display mails sent by the current wiki unless we're on the main wiki

...l-send-api/src/main/java/org/xwiki/mail/MailListener.java

...ail-send-api/src/main/java/org/xwiki/mail/MailStatus.java

...send-api/src/test/java/org/xwiki/mail/MailStatusTest.java

...va/org/xwiki/mail/internal/DefaultMailSenderRunnable.java

...main/java/org/xwiki/mail/internal/MemoryMailListener.java

.../java/org/xwiki/mail/internal/MemoryMailListenerTest.java

...storage/src/main/java/org/xwiki/mail/MailStatusStore.java

...in/java/org/xwiki/mail/internal/DatabaseMailListener.java

...ava/org/xwiki/mail/internal/DatabaseMailStatusResult.java

...java/org/xwiki/mail/internal/DatabaseMailStatusStore.java

...m-mail-send-storage/src/main/resources/mailsender.hbm.xml

...ava/org/xwiki/mail/internal/DatabaseMailListenerTest.java

...org/xwiki/mail/internal/DatabaseMailStatusResultTest.java