[#805,!5-p] Memfile and kea-dhcp4 now suppor max-row-errors parameter

[#805,!5-p] Memfile and kea-dhcp4 now suppor max-row-errors parameter

src/bin/dhcp4/dhcp4_lexer.ll
src/bin/dhcp4/dhcp4_parser.yy
    Added max-row-errors

src/lib/database/database_connection.*
src/lib/database/dbaccess_parser.*
    Added max-row-errors

src/lib/database/tests/dbaccess_parser_unittest.cc
    New tests for max-row-errors

src/lib/dhcpsrv/lease_file_loader.h
    Changed logic value of 0 means unlimited

src/lib/dhcpsrv/memfile_lease_mgr.cc
    Memfile_LeaseMgr::loadLeasesFromFiles() - now uses
    connection parmater value for max-row-errors or 0
    if not specified

src/lib/dhcpsrv/tests/lease_file_loader_unittest.cc
    TEST_F(LeaseFileLoaderTest, maxRowErrors4) - new unit test
    to verify max-row-errors operation

src/lib/dhcpsrv/tests/memfile_lease_mgr_unittest.cc
   TEST_F(MemfileLeaseMgrTest, constructor) - added tests for
   max-row-errors