Fix Issue 492: Arkime stops capturing data in Docker SELKS

[Abinav-Prakash]

This pull request fixes Issue 492, where Arkime would stop capturing network traffic in the Docker SELKS environment. The problem occurred because Arkime_capture sometimes started before Elasticsearch was fully ready, preventing proper indexing and causing packet capture to halt. To resolve this, a startup script (start-arkime.sh) was added that waits for Elasticsearch to be available before launching Arkime_capture.