Make the memory reporting multi-process aware (#35863)

So far the memory reporter aggregates reports from all processes, and
runs the system reporter only in the main process. Instead it is
desirable to have per-process reports. We do so by:
- creating a ProcessReports struct that holds includes the pid in
addition to the reports themselves.
- running the system memory reporter also in content processes.
- updating the about:memory page to create one report per process, and
add useful information like the pid and the urls loaded in a given
process.

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![image](https://github.com/user-attachments/assets/0bafe140-539d-4d6a-8316-639309a22d4a)

Signed-off-by: webbeef <me@webbeef.org>

components/constellation/Cargo.toml

@@ -39,6 +39,7 @@ media = { path = "../media" }
 net = { path = "../net" }
 net_traits = { workspace = true }
 parking_lot = { workspace = true }
+profile = { path = "../profile" }
 profile_traits = { workspace = true }
 script_layout_interface = { workspace = true }
 script_traits = { workspace = true }