Add support for repeated sequences under elasticsearch_syntax

## New Feature Description
Recently, repeated sequences [merged](https://github.com/elastic/elasticsearch/pull/75082) into elasticsearch EQL, which will require updates to support this.

Ex:

```sql
sequence
  [process where opcode == 1] by unique_pid
  [file where opcode == 0] by unique_pid with runs=2
  [network where opcode == 0] by unique_pid
```