* EQL: Plug query params into the AstBuilder (#51886)

As the eventType is customizable, plug that into the parser based on the
given request.

(cherry picked from commit 5b4a3a3)

* EQL: Add field resolution and verification (#51872)

Add basic field resolution inside the Analyzer and a basic Verifier to
check for any unresolved fields.

(cherry picked from commit 7087358)

* EQL: Introduce basic execution pipeline (#51809)

Add main classes that form the 'execution' pipeline are added - most of
them have no functionality; the purpose of this PR is to add flesh out
the contract between the various moving parts so that work can start on
them independently.

(cherry picked from commit 9a1bae5)

* EQL: Add AstBuilder to convert to QL tree (#51558)

* EQL: Add AstBuilder visitors
* EQL: Add tests for wildcards and sets
* EQL: Fix licensing
* EQL: Fix ExpressionTests.java license
* EQL: Cleanup imports
* EQL: PR feedback and remove LiteralBuilder
* EQL: Split off logical plan from expressions
* EQL: Remove stray import
* EQL: Add predicate handling for set checks
* EQL: Remove commented out dead code
* EQL: Remove wildcard test, wait until analyzer

(cherry picked from commit a462700)

* EQL grammar updates and tests (#49658)

* EQL: Additional tests and grammar updates
* EQL: Add backtick escaped identifiers
* EQL: Adding keywords to language
* EQL: Add checks for unsupported syntax
* EQL: Testing updates and PR feedback
* EQL: Add string escapes
* EQL: Cleanup grammar for identifier
* EQL: Remove tabs from .eql tests

(cherry picked from commit 6f1890b)