Bring Jupyter to Zed Editing (#12062)

Run any Jupyter kernel in Zed on any buffer (editor):

<img width="1074" alt="image"
src="https://github.com/zed-industries/zed/assets/836375/eac8ed69-d02b-4d46-b379-6186d8f59470">

## TODO

### Lifecycle

* [x] Launch kernels on demand
* [x] Wait for kernel to be started
* [x] Request Kernel info on start
* [x] Show in progress indicator
* [ ] Allow picking kernel (it defaults to first matching language name)
* [ ] Menu for interrupting and shutting down the kernel
* [ ] Drop running kernels once editor is dropped

### Media Outputs

* [x] Render text and tracebacks with ANSI color handling
* [x] Render markdown as text
* [x] Render PNG and JPEG images using an explicit height based on
line-height
* ~~Render SVG~~ -- not happening for this PR due to lack of text in SVG
support
* [ ] Process `update_display_data` message and related `display_id`
* [x] Process `page` data from payloads as outputs
* [ ] Render markdown as, well, rendered markdown -- Note: unsure if we
can get line heights here

### Document

* [x] Select code and run
* [x] Run current line
* [x] Clear previous overlapping runs
* [ ] Support running markdown code blocks
* [ ] Action to export session as notebook or output files
* [ ] Action to clear all outputs
* [ ] Delete outputs when lines are deleted

## Other missing features

The following is a list of missing functionality or expectations that
are out of scope for this PR.

### Python Environments

Detecting python environments should probably be done in a separate PR
in tandem with how they're used with LSP. Users likely want to pick an
environment for their project, whether a virtualenv, conda env, pyenv,
poetry backed virtualenv, or the system. Related issues:

* https://github.com/zed-industries/zed/issues/7646
* https://github.com/zed-industries/zed/issues/7808
* https://github.com/zed-industries/zed/issues/7296

### LSP Integration

* Submit `complete_request` messages for completions to interleave
interactive variables with LSP
* LSP for IPython semantics (`%%timeit`, `!ls`, `get_ipython`, etc.)

## Future release notes

- Run code in any editor, whether it's a script or a markdown document

Release Notes:

- N/A

crates/repl/src/runtime_settings.rs

@@ -0,0 +1,66 @@
+use schemars::JsonSchema;
+use serde::{Deserialize, Serialize};
+use settings::{Settings, SettingsSources};
+
+#[derive(Copy, Clone, Default, Debug, Serialize, Deserialize, JsonSchema)]
+#[serde(rename_all = "snake_case")]
+pub enum RuntimesDockPosition {
+    Left,
+    #[default]
+    Right,
+    Bottom,
+}
+
+#[derive(Debug, Default)]
+pub struct JupyterSettings {
+    pub enabled: bool,
+    pub dock: RuntimesDockPosition,
+}
+
+#[derive(Clone, Serialize, Deserialize, JsonSchema, Debug)]
+pub struct JupyterSettingsContent {
+    /// Whether the Runtimes feature is enabled.
+    ///
+    /// Default: `false`
+    enabled: Option<bool>,
+    /// Where to dock the runtimes panel.
+    ///
+    /// Default: `right`
+    dock: Option<RuntimesDockPosition>,
+}
+
+impl Default for JupyterSettingsContent {
+    fn default() -> Self {
+        JupyterSettingsContent {
+            enabled: Some(false),
+            dock: Some(RuntimesDockPosition::Right),
+        }
+    }
+}
+
+impl Settings for JupyterSettings {
+    const KEY: Option<&'static str> = Some("jupyter");
+
+    type FileContent = JupyterSettingsContent;
+
+    fn load(
+        sources: SettingsSources<Self::FileContent>,
+        _cx: &mut gpui::AppContext,
+    ) -> anyhow::Result<Self>
+    where
+        Self: Sized,
+    {
+        let mut settings = JupyterSettings::default();
+
+        for value in sources.defaults_and_customizations() {
+            if let Some(enabled) = value.enabled {
+                settings.enabled = enabled;
+            }
+            if let Some(dock) = value.dock {
+                settings.dock = dock;
+            }
+        }
+
+        Ok(settings)
+    }
+}