[DOCS] Create a new page for grok content in scripting docs (#73118)

* [DOCS] Moving grok to its own scripting page

* Adding examples

* Updating cross link for grok page

* Adds same runtime field in a search request for #73262

* Clarify titles and shift navigation

* Incorporating review feedback

* Updating cross-link to Painless

Author: Adam Locke

docs/reference/ingest/processors/grok.asciidoc

@@ -8,52 +8,13 @@ Extracts structured fields out of a single text field within a document. You cho
 extract matched fields from, as well as the grok pattern you expect will match. A grok pattern is like a regular
 expression that supports aliased expressions that can be reused.
 
-This tool is perfect for syslog logs, apache and other webserver logs, mysql logs, and in general, any log format
-that is generally written for humans and not computer consumption.
 This processor comes packaged with many
 https://github.com/elastic/elasticsearch/blob/{branch}/libs/grok/src/main/resources/patterns[reusable patterns].
 
 If you need help building patterns to match your logs, you will find the
 {kibana-ref}/xpack-grokdebugger.html[Grok Debugger] tool quite useful! 
 The https://grokconstructor.appspot.com[Grok Constructor] is also a useful tool.
 
-[[grok-basics]]
-==== Grok Basics
-
-Grok sits on top of regular expressions, so any regular expressions are valid in grok as well.
-The regular expression library is Oniguruma, and you can see the full supported regexp syntax
-https://github.com/kkos/oniguruma/blob/master/doc/RE[on the Oniguruma site].
-
-Grok works by leveraging this regular expression language to allow naming existing patterns and combining them into more
-complex patterns that match your fields.
-
-The syntax for reusing a grok pattern comes in three forms: `%{SYNTAX:SEMANTIC}`, `%{SYNTAX}`, `%{SYNTAX:SEMANTIC:TYPE}`.
-
-The `SYNTAX` is the name of the pattern that will match your text. For example, `3.44` will be matched by the `NUMBER`
-pattern and `55.3.244.1` will be matched by the `IP` pattern. The syntax is how you match. `NUMBER` and `IP` are both
-patterns that are provided within the default patterns set.
-
-The `SEMANTIC` is the identifier you give to the piece of text being matched. For example, `3.44` could be the
-duration of an event, so you could call it simply `duration`. Further, a string `55.3.244.1` might identify
-the `client` making a request.
-
-The `TYPE` is the type you wish to cast your named field. `int`, `long`, `double`, `float` and `boolean` are supported types for coercion.
-
-For example, you might want to match the following text:
-
-[source,txt]
---------------------------------------------------
-3.44 55.3.244.1
---------------------------------------------------
-
-You may know that the message in the example is a number followed by an IP address. You can match this text by using the following
-Grok expression.
-
-[source,txt]
---------------------------------------------------
-%{NUMBER:duration} %{IP:client}
---------------------------------------------------
-
 [[using-grok]]
 ==== Using the Grok Processor in a Pipeline