add oidcfed support

cmd/mytoken-server/main.go

cmd/mytoken-server/mytoken-setup/setup.go

config/example-config.yaml

go.mod

go.sum

internal/config/config.go

internal/db/dbrepo/authcodeinforepo/state/state.go

internal/endpoints/configuration/configurationEndpoint.go

internal/endpoints/consent/consent.go

internal/endpoints/federation/entityStatement.go

internal/endpoints/revocation/revocationEndpoint.go

internal/endpoints/token/access/accessTokenEndpoint.go

internal/endpoints/token/mytoken/mytokenEndpoint.go

internal/jws/jws.go

internal/model/provider.go

internal/mytoken/mytokenHandler.go

internal/mytoken/pkg/mytoken.go

internal/mytoken/restrictions/restriction.go

internal/oidc/authcode/authcode.go

internal/oidc/oidcfed/authcode.go