Polars lazy refactor (#12669)

This moves to predominantly supporting only lazy dataframes for most
operations. It removes a lot of the type conversion between lazy and
eager dataframes based on what was inputted into the command.

For the most part the changes will mean:
* You will need to run `polars collect` after performing operations
* The into-lazy command has been removed as it is redundant.
* When opening files a lazy frame will be outputted by default if the
reader supports lazy frames

A list of individual command changes can be found
[here](https://hackmd.io/@nucore/Bk-3V-hW0)

---------

Co-authored-by: Ian Manske <ian.manske@pm.me>

crates/nu_plugin_polars/Cargo.toml

@@ -34,6 +34,7 @@ polars-arrow = { version = "0.39"}
 polars-ops = { version = "0.39"}
 polars-plan = { version = "0.39", features = ["regex"]}
 polars-utils = { version = "0.39"}
+polars-lazy = { version = "0.39"}
 typetag = "0.2"
 uuid = { version = "1.7", features = ["v4", "serde"] }
 

crates/nu_plugin_polars/src/dataframe/eager/mod.rs

@@ -1,22 +1,11 @@
 mod append;
-mod cast;
 mod columns;
-mod drop;
-mod drop_duplicates;
-mod drop_nulls;
 mod dummies;
-mod filter_with;
-mod first;
-mod get;
-mod last;
-mod melt;
 mod open;
 mod query_df;
-mod rename;
 mod sample;
 mod schema;
 mod shape;
-mod slice;
 mod sql_context;
 mod sql_expr;
 mod summary;
@@ -28,30 +17,18 @@ mod to_df;
 mod to_json_lines;
 mod to_nu;
 mod to_parquet;
-mod with_column;
 
 use crate::PolarsPlugin;
 
 pub use self::open::OpenDataFrame;
 pub use append::AppendDF;
-pub use cast::CastDF;
 pub use columns::ColumnsDF;
-pub use drop::DropDF;
-pub use drop_duplicates::DropDuplicates;
-pub use drop_nulls::DropNulls;
 pub use dummies::Dummies;
-pub use filter_with::FilterWith;
-pub use first::FirstDF;
-pub use get::GetDF;
-pub use last::LastDF;
-pub use melt::MeltDF;
 use nu_plugin::PluginCommand;
 pub use query_df::QueryDf;
-pub use rename::RenameDF;
 pub use sample::SampleDF;
 pub use schema::SchemaCmd;
 pub use shape::ShapeDF;
-pub use slice::SliceDF;
 pub use sql_context::SQLContext;
 pub use summary::Summary;
 pub use take::TakeDF;
@@ -62,28 +39,16 @@ pub use to_df::ToDataFrame;
 pub use to_json_lines::ToJsonLines;
 pub use to_nu::ToNu;
 pub use to_parquet::ToParquet;
-pub use with_column::WithColumn;
 
 pub(crate) fn eager_commands() -> Vec<Box<dyn PluginCommand<Plugin = PolarsPlugin>>> {
     vec![
         Box::new(AppendDF),
-        Box::new(CastDF),
         Box::new(ColumnsDF),
-        Box::new(DropDF),
-        Box::new(DropDuplicates),
-        Box::new(DropNulls),
         Box::new(Dummies),
-        Box::new(FilterWith),
-        Box::new(GetDF),
         Box::new(OpenDataFrame),
-        Box::new(MeltDF),
         Box::new(Summary),
-        Box::new(FirstDF),
-        Box::new(LastDF),
-        Box::new(RenameDF),
         Box::new(SampleDF),
         Box::new(ShapeDF),
-        Box::new(SliceDF),
         Box::new(SchemaCmd),
         Box::new(TakeDF),
         Box::new(ToNu),
@@ -94,6 +59,5 @@ pub(crate) fn eager_commands() -> Vec<Box<dyn PluginCommand<Plugin = PolarsPlugi
         Box::new(ToJsonLines),
         Box::new(ToParquet),
         Box::new(QueryDf),
-        Box::new(WithColumn),
     ]
 }