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/dom/history.rs

@@ -5,6 +5,7 @@
 use std::cell::Cell;
 use std::cmp::Ordering;
 
+use base::IpcSend;
 use base::id::HistoryStateId;
 use constellation_traits::{
     ScriptToConstellationMessage, StructuredSerializedData, TraversalDirection,
@@ -13,7 +14,7 @@ use dom_struct::dom_struct;
 use js::jsapi::Heap;
 use js::jsval::{JSVal, NullValue, UndefinedValue};
 use js::rust::{HandleValue, MutableHandleValue};
-use net_traits::{CoreResourceMsg, IpcSend};
+use net_traits::CoreResourceMsg;
 use profile_traits::ipc;
 use profile_traits::ipc::channel;
 use servo_url::ServoUrl;