[3916] Use stored procedures for MySQL lease dumps

[3916] Use stored procedures for MySQL lease dumps

src/bin/admin/kea-admin.in
    src/bin/admin/kea-admin.in
        get_dump_query() - modified SQL text returned for MySQL backend
        which calls stored procedures to produce lease dumps  rather than
        SQL text from lease_dump_<version>.sh

src/bin/admin/scripts/mysql/Makefile.am
    removed entries for leave_dump_<version>.sh files

src/bin/admin/scripts/mysql/dhcpdb_create.mysql
    Added sql to create stored procedures for lease dumps:
        lease4DumpHeader
        lease4DumpData
        lease6DumpHeader
        lease6DumpData

src/bin/admin/scripts/pgsql/dhcpdb_create.pgsql
    Changes table references in lease6DumpData() to match
    convention used in MySQL lease6DumpData()

src/bin/admin/tests/mysql_tests.sh.in
    mysql_lease4_dump_test() - change lease4 test leases to have differing
    values for lease4.state

    mysql_lease6_dump_test() - change lease4 test leases to have differing
    values for lease6.state

mysql.lease4_dump_test.reference.csv
mysql.lease6_dump_test.reference.csv
    Changed reference files to use lease_state.name values rather than
    lease.state to match dump query output and  new test data

src/bin/admin/scripts/mysql
    deleted the following files as they are now obsolete
        leave_dump_1.0.sh
        leave_dump_2.0.sh
        leave_dump_3.0.sh
        leave_dump_4.0.sh
    Makefile.am - removed entries for deleted lease dump scripts