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/shared/base/Cargo.toml

@@ -19,10 +19,13 @@ ipc-channel = { workspace = true }
 malloc_size_of = { workspace = true }
 malloc_size_of_derive = { workspace = true }
 parking_lot = { workspace = true }
+rayon = { workspace = true }
 serde = { workspace = true }
+serde_json = { workspace = true }
 servo_config = { path = "../../config" }
 time = { workspace = true }
 webrender_api = { workspace = true }
+log = { workspace = true }
 
 [target.'cfg(any(target_os = "macos", target_os = "ios"))'.dependencies]
 mach2 = { workspace = true }