[#36737359]
Refactor the behavior of loading symbolic modules from cache by renaming
methods so it's clearer what they do and ensure that cached modules from
Fastlibs and directories can both be loaded, which was not previously
possible since the demand_load_module only called load_module_from_file.
[#36737359]
When starting msfconsole, 'bundler/setup' is not required, the
'msf/env/gemcache' is required instead. Unlike 'bundler/setup' the
msf/env gemcache does not do the automatic requires for gems in the
cache, so explicit requires on 'active_support/concern' is needed to get
ActiveSupport::Concern defined. (I could have done require
'active_support' to match the behavior of 'bundler/setup', but a smaller
require seemed more appropriate.
[Fixes#36737359]
Refactor Msf::ModuleManager into concerns so its easier to understand and
duplicate code can be made DRY. The refactoring also ensures that when
loading from directories, Fastlibs, or reloading, the wrapper module will
always be named so that activesupport/dependencies will function.
Luke Imhoff