Obtain postmaster_address and hostname from mail_storage_settings.

src/lib-sieve/plugins/enotify/mailto/ntfy-mailto.c

src/lib-sieve/plugins/notify/cmd-notify.c

src/lib-sieve/plugins/vacation/cmd-vacation.c

src/lib-sieve/plugins/vnd.dovecot/report/cmd-report.c

src/lib-sieve/sieve-actions.c

src/lib-sieve/sieve-address-source.c

src/lib-sieve/sieve-common.h

src/lib-sieve/sieve-types.h

src/lib-sieve/sieve.c

src/plugins/imapsieve/imap-sieve.c

src/plugins/lda-sieve/lda-sieve-plugin.c

src/sieve-tools/sieve-filter.c

src/sieve-tools/sieve-test.c

src/testsuite/testsuite-mailstore.c

src/testsuite/testsuite-script.c

src/testsuite/testsuite.c