fix: load order for config

[metaist]

Currently, config values are loaded before CLI arguments (argv), which is correct. Except that CLI arguments also include default values. Which means that default values are superseding config values.

The order I'd like (later values winning):

• default values
• config values
• CLI arguments

But this implies that we need to know which of the docopt values are default and which happen to have the same value as the default.

[metaist]

Maybe #17 solves this (i.e. if you avoid docopt defaults and use class/dataclass defaults). You load the config values (anything not loaded stays with the class default) and then the CLI values.

We should still keep #13 vendorized because the docopt name can clash.