[ES|QL] Add date math syntax and autocomplete support (elastic#166058)

## Summary

This PR adds support for date math in ES|QL providing an improved
autocompleting feature for the `EVAL` command:

* ✨ auto close brackets in monaco


![esql_date_math_support_autoclose](https://github.com/elastic/kibana/assets/924948/657a52e5-20ce-46e6-a138-b1f58184db27)


* ✨ support date math syntax
* ✨ improve EVAL autocomplete in various ways
* provide date duration suggestions with single unit after math
operations
* provide date duration suggestions if quantifier has been declared
already
* provide math signs based on context ( if `EVAL` is in duration mode
just `+`, `-`, otherwise all 4)
* provide math commands based on context (if `EVAL` is in duration mode
only functions who return a date, otherwise all of them)
* provide date duration suggestions only when `EVAL` is in duration mode
* provide date duration suggestions as first argument for date supported
functions
  * extended grammar to support also plural versions of duration units


![esql_date_math_support](https://github.com/elastic/kibana/assets/924948/7bf48265-1c47-45ac-a345-2dd320c8e431)


### Checklist

Delete any items that are not applicable to this PR.

- [x] Any text added follows [EUI's writing
guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/packages/kbn-i18n/README.md)
- [x]
[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials
- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios

packages/kbn-monaco/src/esql/antlr/esql_lexer.g4

@@ -91,6 +91,16 @@ DATE_LITERAL
     | 'second'
     | 'minute'
     | 'hour'
+    | 'week'
+    | 'millisecond'
+    | 'years'
+    | 'months'
+    | 'days'
+    | 'seconds'
+    | 'minutes'
+    | 'hours'
+    | 'weeks'
+    | 'milliseconds'
     ;
 
 AND : 'and';

packages/kbn-monaco/src/esql/antlr/esql_parser.g4

@@ -98,6 +98,10 @@ mathEvalFn
     : mathFunctionIdentifier LP (mathFunctionExpressionArgument (COMMA mathFunctionExpressionArgument)*)? RP
     ;
 
+dateExpression
+   : quantifier=number DATE_LITERAL
+   ;
+
 operatorExpression
     : primaryExpression
     | mathFn
@@ -110,6 +114,7 @@ operatorExpression
 primaryExpression
     : constant
     | qualifiedName
+    | dateExpression
     | LP booleanExpression RP
     | identifier LP (booleanExpression (COMMA booleanExpression)*)? RP
     ;
@@ -173,7 +178,7 @@ mathFunctionExpressionArgument
    | string
    | number
    | operatorExpression
-   | number (DATE_LITERAL)
+   | dateExpression
    | comparison
    ;