Dear Maintainer,

Background:
Dovecot's sieve plugin allows for server-side mail filtering scripts.  These
are typically stored on a per-user basis.  It also allows for a server default
script to be run if there are no user scripts for that user, and also both
"before" and "after" directories where a series of scripts will be run before
and after the user script is run.

Debian's dovecot-sieve package does not create the directory where the
server default script lives.  By (ug) default, this location is:
/usr/lib/dovecot/sieve
And the file to be put in that location would be default.sieve and then
compiled.

Debian also does not create the before or after directories.  There is
no default location for them, but the first suggested location for it given in
/etc/dovecot/90-sieve.conf is:
#sieve_before = /var/lib/dovecot/sieve.d

Request:
1) I propose that the dovecot-sieve package create the default directory that
holds default.sieve.

2) I propose a sample default.sieve script be stored in the above directory.
Less as an actual sample, and more as a marker for "this is where it goes"

3) I propose that the first suggested location for the "sieve_before" directory
be changed to be a subdirectory of the above:
#sieve_before = /var/lib/dovecot/sieve/sieve.d

4) I propose a short readme be placed in 3)'s directory.  Again, mostly just
as a marker for "this is where the before scripts go"


Thus the directory structure I propose is:

/var/lib/dovecot/sieve/
                      ├── default.sieve.sample
                      └── sieve.d/
                                 └── readme.before

I would be happy to provide the files proposed in #2 and #4.