Add ability to map <TAB> and <C-I> separately like XTerm or iTerm2 have done

Is your feature request about something that is currently impossible or hard to do? Please describe the problem.
Currently we can't remap for example <TAB> and <C-I> separately, they both always do the same thing.

Describe the solution you'd like
Would be nice if these, and other control keys (<CR> and <C-M>, <BS> and <C-H> etc.), could be mapped separately.

Additional context
<TAB> and <C-I> can already be mapped separately in a Vim 8.2 running XTerm using modifyOtherKeys https://invisible-island.net/xterm/modified-keys.html or in iTerm2 when 'Control sequences can enable modifyOtherKeys mode' has been enabled from Preferences -> Profiles -> Keys.

One can easily test if the keys get registered separately with:

nnoremap <C-I> :echom "Ctrl-I was pressed"<CR>
nnoremap <TAB> :echom "Tab was pressed"<CR>

Commencez par reproduire le comportement des mappings avec les deux commandes nnoremap de l’issue, puis consultez la documentation de XTerm modifyOtherKeys et comparez-la avec la gestion des entrées clavier de MacVim. Le travail est terminé lorsque et , ainsi que les paires de touches de contrôle analogues, peuvent déclencher des mappings distincts et que les commandes d’exemple affichent des messages différents.