Fast grok access in painless

[stu-elastic]

We need to precompile the pattern for grok access to be fast.

We can use a compiler phase for this. That precludes passing in patterns as params and, for the initial release, precludes custom patterns.

Extensions:

• Custom patterns can be added after we think about the API.

depends on: #51955, #49873

ref: #60659

[elasticmachine]

Pinging @elastic/es-core-infra (:Core/Infra/Scripting)

[stu-elastic]

Not on the radar, will reopen if necessary.

[javanna]

I opened #73468 as a follow-up to allow custom pattern definitions, but grok has already been made available in painless as a function. Closing then.