This is a very large change which turns the post Config function in
backends into a state based call and response system so that
alternative user interfaces can be added.
The existing config logic has been converted, but it is quite
complicated and folloup commits will likely be needed to fix it!
Follow up commits will add a command line and API based way of using
this configuration system.
Includes adding support for additional size input suffix Mi and MiB, treated equivalent to M.
Extends binary suffix output with letter i, e.g. Ki and Mi.
Centralizes creation of bit/byte unit strings.
Restructuring of config code in v1.55 resulted in config
file being loaded early at process startup. If configuration
file is encrypted this means user will need to supply the password,
even when running commands that does not use config.
This also lead to an issue where mount with --deamon failed to
decrypt the config file when it had to prompt user for passord.
Fixes#5236Fixes#5228
This splits config.go into ui.go for the user interface functions and
authorize.go for the implementation of `rclone authorize`.
It also moves the tests into the correct places (including one from
obscure which was in the wrong place).
