Provide config.json file for synthesizing user_project_wrapper

[d-m-bailey]

The current openlane/user_project_wrapper/config.json file has "SYNTH_ELABORATE_ONLY": 1. This causes the top level to only be routed and there is no way to add hi/low ties or solve (or maybe even detect) timing errors. While this might be fine for some designs, it would be helpful to have a config.json file that would synthesize the top level while adding taps and decaps, and fixing timing errors. For example, config.hard.json and config.soft.json.