Extract paths out of util (#13182)

This PR extracts the definition of the various Zed paths out of `util`
and into a new `paths` crate.

`util` is for generic utils, while these paths are Zed-specific. For
instance, `gpui` depends on `util`, and it shouldn't have knowledge of
these paths, since they are only used by Zed.

Release Notes:

- N/A

crates/extension/Cargo.toml

@@ -33,6 +33,7 @@ language.workspace = true
 log.workspace = true
 lsp.workspace = true
 node_runtime.workspace = true
+paths.workspace = true
 project.workspace = true
 release_channel.workspace = true
 schemars.workspace = true

crates/extension/src/extension_store.rs

@@ -36,6 +36,7 @@ use language::{
     LanguageConfig, LanguageMatcher, LanguageQueries, LanguageRegistry, QUERY_FILENAME_PREFIXES,
 };
 use node_runtime::NodeRuntime;
+use paths::EXTENSIONS_DIR;
 use project::ContextProviderWithTasks;
 use release_channel::ReleaseChannel;
 use semantic_version::SemanticVersion;
@@ -51,7 +52,7 @@ use std::{
 };
 use theme::{ThemeRegistry, ThemeSettings};
 use url::Url;
-use util::{maybe, paths::EXTENSIONS_DIR, ResultExt};
+use util::{maybe, ResultExt};
 use wasm_host::{
     wit::{is_supported_wasm_api_version, wasm_api_version_range},
     WasmExtension, WasmHost,