fix moduleName to support npm config/mirrors

[plandem]

Environment Information

• OS: any
• Node Version: any
• NPM Version: any
• C++ Toolchain: any
• confluent-kafka-javascript version: 1.5.0

Steps to Reproduce

library uses such confluent-kafka-javascript as module_name for node-pre-gyp. but:

1. node-pre-gyp replaces first dash with underscore (even last version of node-pre-gyp), https://github.com/mapbox/node-pre-gyp/blob/f9b39484f17955d83cdab42c178a600467fe96bd/lib/util/versioning.js#L312, so validModuleName transforms into confluent_kafka-javascript.

2. npm replaces all dashes for npm config, so it always will transform it into npm_config_confluent_kafka_javascript_binary_host_mirror

3. as result mirror will not be possible to set/use, because this will never work:

const host = process.env['npm_config_' + validModuleName + '_binary_host_mirror'] || package_json.binary.host;

have: npm_config_confluent_kafka_javascript_binary_host_mirror
want: npm_config_confluent_kafka-javascript_binary_host_mirror

So, I see only two options here - a) fix node-pre-gyp or b) change module_name and replace dashes with underscore. suppose b) is easier and npm config is not working anyway

[plandem]

it should be possible to provide mirrors for binaries (node-pre-gyp has such feature) via npm config, e.g.:

npm install @confluentinc/kafka-javascript --confluent_kafka_javascript_binary_host_mirror=file:///prebuilt-kafka-javascript/

- or -

export npm_config_confluent_kafka_javascript_binary_host_mirror=file:///prebuilt-kafka-javascript/
npm install @confluentinc/kafka-javascript

or via .npmrc