##### SUMMARY
`ansible-galaxy collection install` currently requires the user to specify an install path using the `-p` option. Galaxy currently generates and displays the CLI command for installing a collection. There is no way for Galaxy to determine a value for `-p`, and hard coding a default value into Galaxy makes no sense.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
`ansible-galaxy`

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```
ansible 2.10.0.dev0
  config file = /etc/ansible/ansible.cfg
  configured module search path = [u'/Users/chouseknecht/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /Users/chouseknecht/projects/ansible/lib/ansible
  executable location = /Users/chouseknecht/.pyenv/versions/venv27/bin/ansible
  python version = 2.7.14 (default, Nov 14 2017, 23:24:24) [GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.38)]
```

build_parser = parser.add_parser('build', parents=parents,
                                         help='Build an Ansible collection artifact that can be publish to Ansible '
                                              'Galaxy.')
        build_parser.set_defaults(func=self.execute_build)
        build_parser.add_argument('args', metavar='collection', nargs='*', default=('.',),
                                  help='Path to the collection(s) directory to build. This should be the directory '
                                       'that contains the galaxy.yml file. The default is the current working '
                                       'directory.')
        build_parser.add_argument('--output-path', dest='output_path', default='./',
                                  help='The path in which the collection is built to. The default is the current '
                                       'working directory.')
    def add_publish_options(self, parser, parents=None):
        publish_parser = parser.add_parser('publish', parents=parents,
                                           help='Publish a collection artifact to Ansible Galaxy.')
        publish_parser.set_defaults(func=self.execute_publish)
        publish_parser.add_argument('args', metavar='collection_path',
                                    help='The path to the collection tarball to publish.')
        publish_parser.add_argument('--no-wait', dest='wait', action='store_false', default=True,
                                    help="Don't wait for import validation results.")
        publish_parser.add_argument('--import-timeout', dest='import_timeout', type=int, default=0,
                                    help="The time to wait for the collection import process to finish.")
    def post_process_args(self, options):
        options = super(GalaxyCLI, self).post_process_args(options)
        display.verbosity = options.verbosity
        return options
    def run(self):