##### 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)]
```

warnings = []
            for path in roles_path:
                role_path = os.path.expanduser(path)
                if not os.path.exists(role_path):
                    warnings.append("- the configured path %s does not exist." % role_path)
                    continue
                elif not os.path.isdir(role_path):
                    warnings.append("- the configured path %s, exists, but it is not a directory." % role_path)
                    continue
                display.display('# %s' % role_path)
                path_files = os.listdir(role_path)
                path_found = True
                for path_file in path_files:
                    gr = GalaxyRole(self.galaxy, self.api, path_file, path=path)
                    if gr.metadata:
                        _display_role(gr)
            for w in warnings:
                display.warning(w)
            if not path_found:
                raise AnsibleOptionsError("- None of the provided paths was usable. Please specify a valid path with --roles-path")
        return 0
    def execute_publish(self):
        """
        Publish a collection into Ansible Galaxy. Requires the path to the collection tarball to publish.
        """
        collection_path = GalaxyCLI._resolve_path(context.CLIARGS['args'])
        wait = context.CLIARGS['wait']
        timeout = context.CLIARGS['import_timeout']
        publish_collection(collection_path, self.api, wait, timeout)
    def execute_search(self):