Documentation: Update wiki/Usage documentation with note that secret credentials will be stored in bash/zsh/etc history

[henrywintif]

On wiki/Usage the instructions state to pass the client ID and client secret on the command line.

I believe it would be appropriate to add a note that this will most likely add the command (including these secret credentials) to the command history of the shell you are using and perhaps suggest a method to prevent this.

I'm not sure whether bash or zsh default configurations make [space] prepended inputs. My config which isn't very customized does not have this feature enabled.

I just checked and it looks like in ZSH, a user may enable this by running setopt histignorespace, then running the google-drive-ocaml -id ... command with a leading space. After the command is entered they can unset the option with unsetopt histignorespace.

I haven't tested with bash, but it appears that you can use set +o history before and set -o history before and after the command.

[astrada]

Feel free to add the tip to the wiki. It's editable by anyone. Thanks!