Refactor inspector protocol compiles.
This removes the duplication of outputs from core/inspector:protocol_sources to
the compiled version in core:core_generated. A new target is created
core/inspector:protocol that uses get_target_outputs on :protocol_sources to
avoid duplicating the sources list.
To make this easier to implement, the core_config_add and core_config_remove
configs list were moved to core.gni so it can be shared with multiple core
The inspector_protocol.gni file was changed from listing the sources to
defining a template to run the script. This elimiates some duplicated code
between the two users of this script.