Do not inlcude symbols in general project outputs

Symbols data is currently included in resources `extra_data` (what symbols are extracted from binary and source files, and which are matched) are useful for debugging and checking d2d symbol matching processes.

But these long list of symbols are adding to the size of the project outputs and they should not be included in the following inputs:

- JSON output: remove symbols from the resources `extra_data`
- JSON/XLSX outputs: remove symbols lists from the `messages` details

Alternatively we should make the symbols data available to download through the outputs with a seperate JSON option, similarly like we make the SCTK scan/summary data available thorugh the outputs.