Remove cpp-netlib as dependency, replace with Boost.Beast

[anonimal]

Boost.Beast is in beta but will be released in Boost 1.66. Something like Boost.Beast is what we originally wanted when implementing cpp-netlib but Boost.Beast was not really around nor usable enough at the time (cpp-netlib went in the direction of Boost but, for various reasons, bailed and now appear to be a dead project).

Boost.Beast plans on implementing a URI parser. When that happens, we should drop cpp-netlib entirely. In the meantime, we can also consider a Boost.Beast refactor and simply keep the URI lib from cpp-netlib.

Referencing:

• Security Vulnerability: Incorrect handling of SSL_R_SHORT_READ cpp-netlib/cpp-netlib#670
• [Feature Request] URI parser boostorg/beast#787
• Review cpp-netlib for full implementation #155 (comment)

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[anonimal]

NOTICE: THIS ISSUE HAS BEEN MOVED TO GitLab. Please continue the discussion there. See #1013 for details.