##### 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)]
```

remove_parser = parser.add_parser('remove', parents=parents, help='Delete roles from roles_path.')
        remove_parser.set_defaults(func=self.execute_remove)
        remove_parser.add_argument('args', help='Role(s)', metavar='role', nargs='+')
    def add_delete_options(self, parser, parents=None):
        delete_parser = parser.add_parser('delete', parents=parents,
                                          help='Removes the role from Galaxy. It does not remove or alter the actual '
                                               'GitHub repository.')
        delete_parser.set_defaults(func=self.execute_delete)
    def add_list_options(self, parser, parents=None):