Reportportal-client

Fixed
- Python 3.7 support, by HardNorth
- Launch UUID attribute for AIO clients, by HardNorth
- Http timeout bypass for Sync Client, by HardNorth

Fixed
- Attribute truncation for every method with attributes, by HardNorth

Fixed
- Multipart file upload for Async clients, by HardNorth

Added
- `RP` class in `reportportal_client.client` module as common interface for all ReportPortal clients, by HardNorth
- `reportportal_client.aio` with asynchronous clients and auxiliary classes, by HardNorth
- Dependency on `aiohttp` and `certifi`, by HardNorth
Changed
- RPClient class does not use separate Thread for log processing anymore, by HardNorth
- Use `importlib.metadata` package for distribution data extraction for Python versions starting 3.8, by HardNorth
- `helpers.verify_value_length` function updated to truncate attribute keys also and reveal attributes were truncated, by HardNorth
Removed
- Dependency on `six`, by HardNorth

Changed
- Unified ReportPortal product naming, by HardNorth
- `RPClient` internal item stack implementation changed to `LifoQueue` to maintain concurrency better, by HardNorth
Removed
- Unused `delayed_assert` dependency, by HardNorth

Added
- `launch_uuid_print` and `print_output` arguments in `RPClient` class constructor, by HardNorth
Removed
- Python 2.7, 3.6 support, by HardNorth