Refactor code using helper macros str_strip_0x push_if_some def_with_opt_param

[dimxy]

A few helper macros were added which make code more compact:

• str_strip_0x - strips 0x prefix from str with hex
• push_if_some - pushes (key, value as string) into array if value is Some
• def_with_opt_param - adds a with_... method in a struct implementing Builder pattern

Suggestion is to use these macros throughout the codebase.