captouch api change: moved from `pads` to `position`

Important note: This does NOT include a version number bump due to personal policy. As long as the version number remains unchanged the app store will not update its cache, so to "apply" these changes please add a seperate commit that increments the metadata->version field in flow3r.toml.

pads is deprecated and removed. position is deprecated as well but won't be removed until flow3r v2.0. To use the new normalized pos api, use .pos.imag > 0.3 instead of .position[1] > 10000 (conversion factor about 1/35000). Since this API does not exist on flow3r v1.3 yet we opted for this currently more universally compatible option here.

We can change the commit message to be more succinct if you prefer.