Gtrending

* Add `gtrending developers --sponsorable`
* Update README and project metadata

* There's a certificate issue with gtrend.yapie.me which gtrending was using, now we scrape github.com/trending ourselves so it no longer relies on an external API
* Added `sponsorable` option, like how GitHub added it, which can filter trending developers based on whether they allow sponsors
* Reflected the same in documentation
* Switch development packaging to use poetry package manager

- Added CLI usage (55 by nkitsaini)
- Validating spoken language name (41 by palsveningson)
- Fixing spoken language code and name validation introduced in 41
- `convert_*` and more complete `check_*` utility functions (see docs for detailed usage)
- More complete documentation with descriptions and API reference
- Support edge cases for parameters

* Updated docstrings (39 by harsh204016)
* Fixed API reference in docs
* Modifeid wording in several places

33 by deepaks2112

Fixed 32