This changes logic that previously read/wrote from `~/.pkl` to use
XDG base directories (all OSes), and Known Folders locations on Windows.
For example, Pkl will look for `settings.pkl` in:
1. `$XDG_CONFIG_HOME/pkl/settings.pkl`
2. `%APPDATA/pkl/settings.pkl`
3. `~/.pkl/settings.pkl`
4. Path pkl/settings/pkl within `$XDG_CONFIG_DIRS`
5. `/etc/xdg/pkl/settings.pkl`
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Co-authored-by: Florin Ungur <florin@florinungur.com>
* Add `--proxy` and `--no-proxy` CLI flags
* Add property `http` to `pkl:settings`
* Move `EvaluatorSettings` from `pkl:Project` to its own module and add property `http`
* Add support for proxying in server mode, and through Gradle
* Add `setProxy()` to `HttpClient`
* Add documentation
