Remote IO: http support

[madsbk]

Support read directly from a http server like:

import kvikio
import cupy

with kvikio.RemoteFile.from_http_url("http://127.0.0.1:9000/myfile") as f:
    ary = cupy.empty(f.nbytes, dtype="uint8")
    f.read(ary)

This PR is the first step to support S3 using libcurl instead of aws-s3-sdk, which has some pros and cons:

• Pros
  • The global conda pinning issue is less of a problem.
  • We can support other protocols such as http, ftp, and Azure’s storage, without much work.
  • We avoid the free-after-main issue in aws-s3-sdk. This is huge since we would otherwise have to pass around a S3Context in libcudf and cudf to handle shutdown correctly. This is not a problem in libcurl, see https://curl.se/libcurl/c/libcurl.html under Global constants.
• Cons
  • Hard to support the AWS configuration file. We will require the user to either specify the options programmatically or through environment variables like AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY .

[wence-]

C++, not python yet

[wence-]

Nothing more from me, looks good.

[madsbk]

/merge