have `vim_run_command` to effectively run a command in command mode

[saidelike]

At the moment we execute lots of commands from normal mode, for instance:

user.vim_run_normal_exterm(":term\n")

Moreover if you look at neovim-talon or talon-vim and look for all the commands that we try to execute ((": allows to find them all), there is some inconsistency because sometimes we use vim_run_normal/vim_run_normal_exterm, vim_run_commandline/vim_run_commandline_exterm or actions.insert.

However what we should really do is just:

• switch to command mode (which is possibly changing to normal mode and then inserting the key :)
• execute the command from command mode: user.vim_run_command("term\n") (notice there is no :)

[saidelike]

• we need to keep vim_run_command to actually execute vim commands so we don't end up failing if paste() is used when insert()ing something (paste_to_insert_threshold in community / insert_paste_disabled unset in Andreas)
• also if paste() is used when insert()ing something (paste_to_insert_threshold in community / insert_paste_disabled unset in Andreas), we need to disable it in normal mode and visual mode so the motions work