Use newly introduced procd_add_restart_mount_trigger to make sure
postmaster gets started only once PGDATA becomes available.
Relocate socket directory to /var/lib/postgresql to make it possible
to run postgresql inside a ujail.
Use signal for shutdown, so it works nicely with jail.
Allow multiple script in UCI 'config postgres-db' to be a list and
run them in order listed.
User more silent methods to check for db or role existence and make
it easy to create several databases owned by the same user by passing
the same credentials multiple times.
Remove disfunctional reload handler.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

Extend UCI mechanics to allow pre-populating a newly created
database by executing SQL statements from a scripts file.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

* convert package build to use host-build for ecpg, pg_config and zic
 * introduce /lib/functions/postgresql.sh to be used by packages
   requiring a postgres database to exist as well as postgres' init
 * no longer require shadow-su, patch pg_ctl to setuid() ifself instead
 * auto-create database directory if there is enough free space
 * auto-create databases configured in UCI
 * remove some dead uci config options
 * grab maintainership

Signed-off-by: Daniel Golle <daniel@makrotopia.org>