Support tasks from rust-analyzer (#28359)

(and any other LSP server in theory, if it exposes any LSP-ext endpoint
for the same)

Closes https://github.com/zed-industries/zed/issues/16160

* adds a way to disable tree-sitter tasks (the ones from the plugins,
enabled by default) with
```json5
"languages": {
  "Rust": "tasks": {
      "enabled": false
    }
  }
}
```
language settings

* adds a way to disable LSP tasks (the ones from the rust-analyzer
language server, enabled by default) with
```json5
"lsp": {
  "rust-analyzer": {
    "enable_lsp_tasks": false,
  }
}
```

* adds rust-analyzer tasks into tasks modal and gutter:

<img width="1728" alt="modal"
src="https://github.com/user-attachments/assets/22b9cee1-4ffb-4c9e-b1f1-d01e80e72508"
/>

<img width="396" alt="gutter"
src="https://github.com/user-attachments/assets/bd818079-e247-4332-bdb5-1b7cb1cce768"
/>


Release Notes:

- Added tasks from rust-analyzer

crates/project/src/project_settings.rs

@@ -25,7 +25,7 @@ use std::{
     time::Duration,
 };
 use task::{TaskTemplates, VsCodeTaskFile};
-use util::ResultExt;
+use util::{ResultExt, serde::default_true};
 use worktree::{PathChange, UpdatedEntriesSet, Worktree, WorktreeId};
 
 use crate::{
@@ -278,12 +278,28 @@ pub struct BinarySettings {
     pub ignore_system_version: Option<bool>,
 }
 
-#[derive(Clone, Debug, Default, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
 #[serde(rename_all = "snake_case")]
 pub struct LspSettings {
     pub binary: Option<BinarySettings>,
     pub initialization_options: Option<serde_json::Value>,
     pub settings: Option<serde_json::Value>,
+    /// If the server supports sending tasks over LSP extensions,
+    /// this setting can be used to enable or disable them in Zed.
+    /// Default: true
+    #[serde(default = "default_true")]
+    pub enable_lsp_tasks: bool,
+}
+
+impl Default for LspSettings {
+    fn default() -> Self {
+        Self {
+            binary: None,
+            initialization_options: None,
+            settings: None,
+            enable_lsp_tasks: true,
+        }
+    }
 }
 
 #[derive(Copy, Clone, Debug, Serialize, Deserialize, JsonSchema)]