Enable SSH Agent forwarding on MacOS

[magyargergo]

It would be really nice to be able to pass docker arguments in the hosts files. Reason being I'm facing with an SSH issue Host default unreachable: SocketError - getaddrinfo: nodename nor servname provided, or not known and I googled around when I found this first docker/for-mac#410 (comment) and later in the official doc.

$ gem env   
RubyGems Environment:
  - RUBYGEMS VERSION: 3.0.9
  - RUBY VERSION: 2.5.1 (2018-03-29 patchlevel 57) [x86_64-darwin22]
  - INSTALLATION DIRECTORY: /Users/gmagyar/.rvm/gems/ruby-2.5.1
  - USER INSTALLATION DIRECTORY: /Users/gmagyar/.gem/ruby/2.5.0
  - RUBY EXECUTABLE: /Users/gmagyar/.rvm/rubies/ruby-2.5.1/bin/ruby
  - GIT EXECUTABLE: /usr/local/bin/git
  - EXECUTABLE DIRECTORY: /Users/gmagyar/.rvm/gems/ruby-2.5.1/bin
  - SPEC CACHE DIRECTORY: /Users/gmagyar/.gem/specs
  - SYSTEM CONFIGURATION DIRECTORY: /Users/gmagyar/.rvm/rubies/ruby-2.5.1/etc
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86_64-darwin-22
  - GEM PATHS:
     - /Users/gmagyar/.rvm/gems/ruby-2.5.1
     - /Users/gmagyar/.rvm/rubies/ruby-2.5.1/lib/ruby/gems/2.5.0
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :backtrace => false
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - https://rubygems.org/
  - SHELL PATH:
     - /usr/local/bin
     - /usr/local/sbin
     - /Users/gmagyar/.rvm/gems/ruby-2.5.1/bin
     - /Users/gmagyar/.rvm/gems/ruby-2.5.1@global/bin
     - /Users/gmagyar/.rvm/rubies/ruby-2.5.1/bin
     - /Users/gmagyar/.rvm/bin
     - /Users/gmagyar/.rbenv/shims
     - /Users/gmagyar/.rbenv/bin
     - /usr/local/opt/mozjpeg/bin
     - ~/tools/arcanist/bin
     - ~/tools/arcanist/bin
     - /Users/gmagyar/.nvm/versions/node/v16.17.0/bin
     - /Users/gmagyar/bin
     - /usr/local/bin
     - /usr/local/bin
     - /System/Cryptexes/App/usr/bin
     - /usr/bin
     - /bin
     - /usr/sbin
     - /sbin
     - /usr/local/go/bin
     - /usr/local/MacGPG2/bin
     - /opt/puppetlabs/bin
     - /opt/puppetlabs/pdk/bin
     - /Library/Apple/usr/bin
     - /Users/gmagyar/.rvm/bin
     - /Users/gmagyar/.rvm/bin

Beaker Docker is at the latest release
Docker version 20.10.23, build 7155243