Improve filtering syntax

[dkumiszhan]

In https://github.com/glaslos/ochi/pull/46 we introduced the initial version of filtering syntax using chevrotain. We need to improve the syntax by adding new features.

Some things to consider:

• Should we support operators like contains or matches?
• Should we support in operator?
• Should we support "unary" clause (for example tcp, ip.src, etc)?
• ~How can we filter by payload?~ https://github.com/honeynet/ochi/pull/57

[ashutosh887]

@dkumiszhan @glaslos If resolved, can we close this issue?