baseurl is not quite right when using STORAGE_EMULATOR_HOST

[jpambrun]

I think this line should read:

    const baseUrl = `${EMULATOR_HOST}/storage/v1` || `${options.apiEndpoint}/storage/v1`;

I guess the intend was to have configurable path, not only the host, but it breaks either bucket api or the object api.

Currently, with the default url, we get

config = {
 apiEndpoint: 'https://storage.googleapis.com',
 baseUrl: 'https://storage.googleapis.com/storage/v1',
 //...
}

while with a EMULATOR_HOST= https://exmaple.com we get

config = {
 apiEndpoint: 'https://exmaple.com',
 baseUrl: 'https://exmaple.com',
 //...
}

As a result, when EMULATOR_HOST is set with https://exmaple.com I can create buckets (the url starts with /storage/v1), but can't upload/download file (url starts with /upload/storage/v1). If I set EMULATOR_HOST to https://exmaple.com/v1/storage/ I have the inverse problem (can't create bucket, but can upload/download)

[stephenplusplus]

cc @jkwlui @frankyn this is the origin discussion: #1161 (comment)

[stephenplusplus]

Thanks for reporting @jpambrun!