Add command_prelude module (#12291)

# Description
When implementing a `Command`, one must also import all the types
present in the function signatures for `Command`. This makes it so that
we often import the same set of types in each command implementation
file. E.g., something like this:
```rust
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
    record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData,
    ShellError, Signature, Span, Type, Value,
};
```

This PR adds the `nu_engine::command_prelude` module which contains the
necessary and commonly used types to implement a `Command`:
```rust
// command_prelude.rs
pub use crate::CallExt;
pub use nu_protocol::{
    ast::{Call, CellPath},
    engine::{Command, EngineState, Stack},
    record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, IntoSpanned,
    PipelineData, Record, ShellError, Signature, Span, Spanned, SyntaxShape, Type, Value,
};
```

This should reduce the boilerplate needed to implement a command and
also gives us a place to track the breadth of the `Command` API. I tried
to be conservative with what went into the prelude modules, since it
might be hard/annoying to remove items from the prelude in the future.
Let me know if something should be included or excluded.

crates/nu-color-config/src/style_computer.rs

@@ -1,16 +1,16 @@
-use crate::text_style::Alignment;
-use crate::{color_record_to_nustyle, lookup_ansi_color_style, TextStyle};
+use crate::{color_record_to_nustyle, lookup_ansi_color_style, text_style::Alignment, TextStyle};
 use nu_ansi_term::{Color, Style};
 use nu_engine::{env::get_config, eval_block};
 use nu_protocol::{
     cli_error::CliError,
+    debugger::WithoutDebug,
     engine::{EngineState, Stack, StateWorkingSet},
     IntoPipelineData, Value,
 };
-use std::collections::HashMap;
-
-use nu_protocol::debugger::WithoutDebug;
-use std::fmt::{Debug, Formatter, Result};
+use std::{
+    collections::HashMap,
+    fmt::{Debug, Formatter, Result},
+};
 
 // ComputableStyle represents the valid user style types: a single color value, or a closure which
 // takes an input value and produces a color value. The latter represents a value which