Support input/output type overrides (configuration/metadata)

Some applications use parsers that are not as standards-compliant or the sops parser introduces issues on it's own (e.g. #751 ).

To workaround those situations, we can create the file via specific type override to binary:

sops --input-type binary --output-type binary test.ini

However, this type information is not saved into the sops metadata inside the encrypted JSON structure.

This makes automatic handling of these cases in decryption (CI/CD/...) unnecessarily complex and application-specific overrides need to be introduced.

Neither can this be specified via the .sops.yaml for creation_rules.

Furthermore, no option exists to "publish" to a local directory, which currently is the only command that supports the omit_extension option, which could have been used as an alternative by using a command as follows instead of the above:

sops test.ini.enc

...which would automatically make sops to fall-back to binary type and allow easily workaround the issue.

For the cases that I have to handle (e.g. configuration for the mozilla/tokenserver), the ideal situation would be:

1. support input_type and output_type in creation_rules
2. additionally store and respect input_type and output_type in sops metadata

Start by tracing how creation_rules are parsed and how input/output types are handled and stored in the sops metadata. Confirm the existing publish-to-directory and omit_extension behavior, then define tests showing that configured input_type and output_type are saved, respected during decryption, and applied when creating files.