Allow usage of path in construct_runtime! (#8801)

* Allow usage of path in construct_runtime!

* Fix whitespace

* Fix whitespace

* Make expand_runtime_metadata accept slice instead of Iterator

* Include Call and Event in construct_runtime for testing

* Migrate impl_outer_event to proc macro

* Fix integrity_test_works

* Update UI test expectations

* Factor in module path while generating enum variant or fn names

* Use ParseStream::lookahead for more helpful error messages

* Remove generating outer_event_metadata

* Ensure pallets with different paths but same last path segment can coexist

* Remove unnecessary generated function

* Migrate decl_outer_config to proc macro

* Add default_filter test for expand_outer_origin

* Allow crate, self and super keywords to appear in pallet path

* Add UI test for specifying empty pallet paths in construct_runtime