Remove `BuiltInWindowFunction` (LogicalPlans)

[alamb]

Which issue does this PR close?

• (Almost closes) https://github.com/apache/datafusion/issues/8709 :tada:!!!
• Follow on https://github.com/apache/datafusion/pull/13201

Rationale for this change

@buraksen and @jcsherin ported the last window function over, so now we can remove the old BuiltInWindowFunction code

This was so tempting a cleanup that I had to give it a try (and I wanted to do some coding)

What changes are included in this PR?

Changes:

1. Remove BuiltInWindowFunction
2. Remove BuiltInWindowFunctionDefinition::BuiltInWindowFunction
3. Remove Protobuf definitions
4. Update code to compile

Are these changes tested?

Yes, by existing CI

[alamb]

There are actually several related "BuiltInWindowExpr" in physical-expr that need to be cleaned up as well (that are no longer related to BuiltInWindowExprs). We may also be able to remove a level of trait.

[jonathanc-n]

@alamb @buraksenn @Omega359 Pretty sure we can now clean up the old window docs, due to the nth_value migration being merged. Lemme see if I can do that really quick

[alamb]

@alamb @buraksenn @Omega359 Pretty sure we can now clean up the old window docs, due to the nth_value migration being merged. Lemme see if I can do that really quick

Yes, we can -- I think that is tracked by

• https://github.com/apache/datafusion/issues/13171

[jcsherin]

LGTM 👍. Thanks @alamb

[alamb]

Thanks @crepererum and @jcsherin for the reviews