Discogs-alert

- new feature: country whitelist & blacklist, the ability to control from where you want to consider releases
- `README.md` improvements
- cleaned up `discogs_alert/utils.py` & added tests
- add the following PR checks
- `ruff` linting for all Python versions >= 3.7
- LFS warning
- `tox`, running pytest for all Python versions >= 3.7

- Adds [ruff](https://github.com/charliermarsh/ruff) as well as a `pre-commit` check
- Added a poetry `pre-commit` check to ensure `pyproject.toml` stays well formatted
- Removed `CHANGELOG.md` (the release history is a much more reliable place to track changes)
- Adds [tox](https://github.com/tox-dev/tox), in preparation for a more rigorous testing setup
- Switches project from GPL —> MIT license
- Improves currency error handling via explicitly raising an exception for unparseable currencies & logging the culprit release

- close the Selenium client after every loop iteration (else these leak & clog the computer with hundreds of chromedrivers)
- fixes the currency parsing for Brazilian Real
- increments the versions of various dependencies & improves `pyproject.toml` dependency specification

- changes to looping logic:
- notifications are sent for all listings found (if there are somehow more than one)
- the discogs & pushbullet API rate limits are taken into account to sleep execution
- the number of API requests overall was reduced
- much improved currency & condition parsing (separate improvements)
- updated dependencies

This releases fixes a few small but critical bugs:
- fixed two separate parsing bugs, introduced due to changes on the Discogs marketplace:
- the media condition elements have a new structure
- the sleeve condition is now sometimes not displayed
- changed the loop to ping the PushBullet API less frequently in order to avoid hitting API limits. This also simplifies the notification logic in `notify.py`
- hid more logs behind the verbose flag so that default, non-verbose execution is clean

**fixes**
+ several currency API bugs
+ several `scrape.py` parsing bugs
+ major bug in checking whether `conditions_satisfied`
+ suppressed noisy webdriver-manager logs
+ better logging throughout the project + more informative within-loop logs
+ better exception handling in `loop.py`

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**adds**
+ Docker support!
+ documentation for running package as a `cron` job
+ scraping robustness improvements

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**misc.**

+ updated dependencies