tile-join metadata generator_options increasing mbtiles size

**What I do**

I have an application where users can add new routes to map. Application calculates each time popularity of routes using complex post filters and regenerates mbtiles. I generate temp mbtiles only for the area of newly added route (bbox). In next step I remove routes within this bbox area from live mbtiles with tile-join -j '{some-long-filer-string}'. After that I merge live mbtiles with temp mbtiles, so I get updated live mbtiles. Visualization works just great! (The idea was taken from this answer: https://github.com/mapbox/tippecanoe/issues/694#issuecomment-449092760)

**The problem:**

Each time I run these steps, with the same GeoJSON data, I get increase in mbtiles file size due to appending command line to mbtiles meta generator_options field.

**The solution?**

To have an option to remove that meta property (since it is not needed according to Mapbox). I have checked the Docs and went briefly through tile-join implementation, please correct me if I'm wrong, but I think this is not possible at the moment?

Test tileJSON file attached
[v3.json.txt](https://github.com/mapbox/tippecanoe/files/4023370/v3.json.txt)

Start by reading the tile-join implementation's metadata handling and inspect the attached v3.json.txt example, focusing on how generator_options is appended during repeated merges. Define done as providing a way to prevent or remove that metadata while preserving the existing live-and-temp MBTiles merge workflow.

Written by the indexing model from the issue text.