Create CmdInfo objects directly in the map and fix one error from clang 11

[chrta]

Next round... (probably the last one for now)

I had a look at compiler warnings etc from clang 11 and fixed a few. My initial intention was to remove new(this)Class(); because of https://isocpp.org/wiki/faq/ctors#init-methods and use c++11 delegating constructor. But since CmdInfo is only used in a map, i instead use only the move constructor and removed the copy constructor (and also the default operator=()).

Summary:

• Create CmdInfo objects directly in the map using move constructor
• delete unused CmdInfo constructors
• fixed a few compiler warnings
• fixed one compiler error from clang 11, see https://github.com/saleyn/erlexec/commit/4f5e9b05f2150d515c16ba0312d51f28ab12adb3