Added local hashcat support in macOS

[shivanraptor]

• In the initialization process, check if Homebrew and hashcat are installed. If not installed, hint the user to install before continue.
• In Hashcat_Cracker, symlink the local hashcat with the missing "hashcat.osx". (TODO: Compare hashcat version)

[s3inlc]

Hashtopolis is made to be able to run multiple hashcat versions on the agent, e.g. if for specific tasks another version is suited better. That's why it should not use the system-wide installed hashcat versions as the agent cannot control these. The way to go for OS X is, to compile the hashcat binary and modules from the source code from Github and then pack a new 7z (structured the same as the binary download from hashcat.net) and place it in a server reachable by the agents. Then just set the URL for the 7z download to that location instead of the hashcat.net download link.