input/logictree: gmpe logic tree has separate parsing and validation
input/logictree: gmpe logic tree has separate parsing and validation


Former-commit-id: d58c3ff4e0a00a138aa5a0cbb8d517ea7032b0bd [formerly b676b6fe0e62c27d3e8527b5513c90ba2bf66656]
Former-commit-id: 52bf7a2d5105c17bd06b39d3cdb5a3c7c678ca4d
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine