Reduce duplication in history path construction (#13475)

# Description
Currently there is a bit of chaos regarding construction of history file
paths. Various pieces of code across a number of crates reimplement the
same/similar logic:
- There is `get_history_path`, but it requires a directory parameter (it
really just joins it with a file name).
- Some places use a const for the directory parameter, others use a
string literal - in all cases the value seems to be `"nushell"`.
- Some places assume the `"nushell"` value, other plumb it down from
close to the top of the call stack.
- Some places use a constant for history file names while others assume
it.

This PR tries to make it so that the history/config path format is
defined in a single places and so dependencies on it are easier to
follow:
- It removes `get_history_path` and adds a `file_path` method to
`HistoryConfig` instead (an extra motivation being, this is a convenient
place that can be used from all creates that need a history file path)
- Adds a `nu_config_dir` function that returns the nushell configuration
directory.
- Updates existing code to rely on the above, effectively removing
duplicate uses of `"nushell"` and `NUSHELL_FOLDER` and assumptions about
file names associated with different history formats

# User-Facing Changes
None

crates/nu-cli/src/repl.rs

@@ -50,7 +50,6 @@ use sysinfo::System;
 pub fn evaluate_repl(
     engine_state: &mut EngineState,
     stack: Stack,
-    nushell_path: &str,
     prerun_command: Option<Spanned<String>>,
     load_std_lib: Option<Spanned<String>>,
     entire_start_time: Instant,
@@ -97,7 +96,7 @@ pub fn evaluate_repl(
 
     unique_stack.set_last_exit_code(0, Span::unknown());
 
-    let mut line_editor = get_line_editor(engine_state, nushell_path, use_color)?;
+    let mut line_editor = get_line_editor(engine_state, use_color)?;
     let temp_file = temp_dir().join(format!("{}.nu", uuid::Uuid::new_v4()));
 
     if let Some(s) = prerun_command {
@@ -213,7 +212,7 @@ pub fn evaluate_repl(
             }
             Err(_) => {
                 // line_editor is lost in the error case so reconstruct a new one
-                line_editor = get_line_editor(engine_state, nushell_path, use_color)?;
+                line_editor = get_line_editor(engine_state, use_color)?;
             }
         }
     }
@@ -243,11 +242,7 @@ fn unescape_for_vscode(text: &mut std::str::Chars) -> Option<char> {
     }
 }
 
-fn get_line_editor(
-    engine_state: &mut EngineState,
-    nushell_path: &str,
-    use_color: bool,
-) -> Result<Reedline> {
+fn get_line_editor(engine_state: &mut EngineState, use_color: bool) -> Result<Reedline> {
     let mut start_time = std::time::Instant::now();
     let mut line_editor = Reedline::create();
 
@@ -258,7 +253,7 @@ fn get_line_editor(
     if let Some(history) = engine_state.history_config() {
         start_time = std::time::Instant::now();
 
-        line_editor = setup_history(nushell_path, engine_state, line_editor, history)?;
+        line_editor = setup_history(engine_state, line_editor, history)?;
 
         perf!("setup history", start_time, use_color);
     }
@@ -1121,7 +1116,6 @@ fn flush_engine_state_repl_buffer(engine_state: &mut EngineState, line_editor: &
 /// Setup history management for Reedline
 ///
 fn setup_history(
-    nushell_path: &str,
     engine_state: &mut EngineState,
     line_editor: Reedline,
     history: HistoryConfig,
@@ -1133,7 +1127,7 @@ fn setup_history(
         None
     };
 
-    if let Some(path) = crate::config_files::get_history_path(nushell_path, history.file_format) {
+    if let Some(path) = history.file_path() {
         return update_line_editor_history(
             engine_state,
             path,
@@ -1409,8 +1403,7 @@ fn trailing_slash_looks_like_path() {
 fn are_session_ids_in_sync() {
     let engine_state = &mut EngineState::new();
     let history = engine_state.history_config().unwrap();
-    let history_path =
-        crate::config_files::get_history_path("nushell", history.file_format).unwrap();
+    let history_path = history.file_path().unwrap();
     let line_editor = reedline::Reedline::create();
     let history_session_id = reedline::Reedline::create_history_session_id();
     let line_editor = update_line_editor_history(