webui: add slow down to 3 secs list polling time
webui: add slow down to 3 secs list polling time

Former-commit-id: 68c19bee3a2be1c21a54bce7a355889fcd742170 [formerly dc348c19bfd1f8f7a28084861f0db385f29ee9ed]
Former-commit-id: e07a8806d42c319e4dc57b6a3cc50bab4760e167
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine