Fix C++ client cannot be built with Boost <=1.53

[BewareMyPower]

Motivation

CentOS 7 is a wide-used Linux system though its softwares of yum source are usually very old. The default Boost version is 1.53 on CentOS 7. However, currently C++ client cannot be built with Boost 1.53 or lower versions.

First, the boost::asio::ssl::context was constructed with a std::shared_ptr<io_service> as its first argument when the Boost version is < 1.54. However, it accepts a io_service& argument. This code error was not exposed because we use higher version Boost when cpp tests were performed.

Second, for Boost < 1.55, there's no boost/predef.h header. The header is used for detecting the byte order of OS and the architecture of CPU.

Modifications

• Fix the wrong construction of boost::asio::ssl::context for Boost < 1.54
• Use conditional macro to exclude the boost/predef.h and use boost/detail/endian.hpp to check byte order. As for the architecture, just use the common case.
• Add a docker build to CI, which builds a docker image with dependencies based on CentOS 7 and build C++ client after it.

Verifying this change

• Make sure that the change passes the CI checks.

This change added tests and can be verified as follows:

• Add a CI to build C++ client on CentOS and dependencies from its default source.

Does this pull request potentially affect one of the following parts:

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API: (yes / no)
• The schema: (yes / no / don't know)
• The default values of configurations: (yes / no)
• The wire protocol: (yes / no)
• The rest endpoints: (yes / no)
• The admin cli options: (yes / no)
• Anything that affects deployment: (yes / no / don't know)

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)
• If a feature is not applicable for documentation, explain why?
• If a feature is not documented yet in this PR, please create a followup issue for adding the documentation

[eolivelli]

This patch cannot be ported to branch-2.7, as it requires CI changes.
CI changed a lot between 2.7 and 2.8