Possible improvements to HTML output from `export_table()`

[strengejacke]

the gt packages got some new updates (https://twitter.com/gt_package/status/1565805423869018112), but also before, gt offered much more stuff we weren't leveraging yet in insight::export_table().

We might look closer into the features of gt and maybe add some more features to export_table()s HTML output. I have no particular stuff in mind, just some nice improvements...

[DominiqueMakowski]

Linking https://github.com/easystats/report/issues/289