Extend exports for new types/kinds

[oubiwann]

Currently we're exporting every Kind of record to csv (Firefox and Chrome), but this really only makes sense for Kind::Password and probably Kind::Account but not for the others. But we can support those as well as full exports with JSON.

Tasks:

• Change export --type to --format
• Add support for --type (kind)
• By default, export firefox and chrome only Kind::Password records
• Add an --include-accounts flag for firefox and chrome exports
• Add JSON serialisation capability
• Add json to the allowed types for export
• If the --type for export is Kind::AsymmetricCrypto, Kind::Certificates, or Kind::ServiceCredentials, set the format to JSON
• If no type is set and no format is set, export all in JSON format
• When exporting to JSON, support limiting by --category
• When exporting to JSON, support limiting by --tags