Pass ParserOptions to the parser (#16220)

## Summary

This is part of the preparation for detecting syntax errors in the
parser from https://github.com/astral-sh/ruff/pull/16090/. As suggested
in [this
comment](https://github.com/astral-sh/ruff/pull/16090/#discussion_r1953084509),
I started working on a `ParseOptions` struct that could be stored in the
parser. For this initial refactor, I only made it hold the existing
`Mode` option, but for syntax errors, we will also need it to have a
`PythonVersion`. For that use case, I'm picturing something like a
`ParseOptions::with_python_version` method, so you can extend the
current calls to something like

```rust
ParseOptions::from(mode).with_python_version(settings.target_version)
```

But I thought it was worth adding `ParseOptions` alone without changing
any other behavior first.

Most of the diff is just updating call sites taking `Mode` to take
`ParseOptions::from(Mode)` or those taking `PySourceType`s to take
`ParseOptions::from(PySourceType)`. The interesting changes are in the
new `parser/options.rs` file and smaller parts of `parser/mod.rs` and
`ruff_python_parser/src/lib.rs`.

## Test Plan

Existing tests, this should not change any behavior.

crates/ruff_python_parser/src/parser/options.rs

@@ -0,0 +1,41 @@
+use ruff_python_ast::PySourceType;
+
+use crate::{AsMode, Mode};
+
+/// Options for controlling how a source file is parsed.
+///
+/// You can construct a [`ParseOptions`] directly from a [`Mode`]:
+///
+/// ```
+/// use ruff_python_parser::{Mode, ParseOptions};
+///
+/// let options = ParseOptions::from(Mode::Module);
+/// ```
+///
+/// or from a [`PySourceType`]
+///
+/// ```
+/// use ruff_python_ast::PySourceType;
+/// use ruff_python_parser::ParseOptions;
+///
+/// let options = ParseOptions::from(PySourceType::Python);
+/// ```
+#[derive(Debug)]
+pub struct ParseOptions {
+    /// Specify the mode in which the code will be parsed.
+    pub(crate) mode: Mode,
+}
+
+impl From<Mode> for ParseOptions {
+    fn from(mode: Mode) -> Self {
+        Self { mode }
+    }
+}
+
+impl From<PySourceType> for ParseOptions {
+    fn from(source_type: PySourceType) -> Self {
+        Self {
+            mode: source_type.as_mode(),
+        }
+    }
+}