Add CQL Query Parser

[gonzalotguerrero]

• Built on Apache Cassandra's CQL ANTLR4 grammar (source)
• Parses SELECT, UPDATE, and DELETE WHERE clauses into a structural typed condition model
• Equality, inequality (>, >=, <, <=), IN, CONTAINS, and CONTAINS KEY conditions, with multi-condition support via AND wrapped in an AndOperation
• Full literal support: strings, integers, floats, booleans, UUIDs, durations (standard quantity-unit, ISO 8601 standard, and ISO 8601 alternative formats), and NULL
• Quoted identifiers and case-insensitive keyword lexing
• 46 parser tests