Reduct-cli

Added:

- `rcli mirror` to copy data from a bucket to another
one, [PR-18](https://github.com/reduct-storage/reduct-cli/pull/18)
- `rcli token` to manage API tokens, [PR-20](https://github.com/reduct-storage/reduct-cli/pull/20)

Added:

- `rcli` alias for `reduct-cli`, [PR-10](https://github.com/reduct-storage/reduct-cli/pull/10)
- Options for server URL and API token to alias add
command, [PR-11](https://github.com/reduct-storage/reduct-cli/pull/11)
- `rcli bucket ls` to list buckets, [PR-13](https://github.com/reduct-storage/reduct-cli/pull/13)
- `rcli bucket show` to browse a bucket, [PR-14](https://github.com/reduct-storage/reduct-cli/pull/14)
- `rcli bucket create` to create a bucket, [PR-15](https://github.com/reduct-storage/reduct-cli/pull/15)
- `rcli bucket update` to update bucket settings, [PR-16](https://github.com/reduct-storage/reduct-cli/pull/16)
- `rcli bucket rm` to remove a bucket, [PR-17](https://github.com/reduct-storage/reduct-cli/pull/17)

Added:

- Add alias commands: add, remove, show, [PR-6](https://github.com/reduct-storage/reduct-cli/pull/6)
- Add `server status` command to check server's status, [PR-9](https://github.com/reduct-storage/reduct-cli/pull/9)

Changed:

- Make alias command more idiomatic, [PR-7](https://github.com/reduct-storage/reduct-cli/pull/7)

Initial release