storage: Move shared functionality to base (#39419)

Part of #39418. See that PR for a full description.

Moves:
- `read_json_from_file`
- `write_json_to_file`
- `IpcSendResult`
- `IpcSend`

Renames:
- `CoreResourceThreadPool` to `ThreadPool` (shorter and more
descriptive, as we use it for more than the core resource thread now)

Signed-off-by: Ashwin Naren <arihant2math@gmail.com>

components/script/webdriver_handlers.rs

@@ -6,6 +6,7 @@ use std::collections::{HashMap, HashSet};
 use std::ffi::CString;
 use std::ptr::NonNull;
 
+use base::IpcSend;
 use base::generic_channel::GenericSender;
 use base::id::{BrowsingContextId, PipelineId};
 use cookie::Cookie;
@@ -27,7 +28,6 @@ use net_traits::CookieSource::{HTTP, NonHTTP};
 use net_traits::CoreResourceMsg::{
     DeleteCookie, DeleteCookies, GetCookiesDataForUrl, SetCookieForUrl,
 };
-use net_traits::IpcSend;
 use script_bindings::codegen::GenericBindings::ShadowRootBinding::ShadowRootMethods;
 use script_bindings::conversions::is_array_like;
 use script_bindings::num::Finite;