Resource-tracker

- Fix don't always round up CPU/GPU recommendations
- Improve error message on missing historical data
- Improve documentation

Relatively major package rewrite to support alternative tracker implementations (other than directly reading from `/proc`). No breaking changes in the public API on Linux.

- Add tracker implementation using `psutil` to support MacOS and Windows
- Fix data issues with the `/proc` implementation after validating with the `psutil` version (e.g. number of processes reported)
- Refactor code for better maintainability
- Add additional unit tests:
- Tracker implementation using `procfs`
- Tracker implementation using `psutil`
- Consistency between tracker implementations
- Metaflow decorators
- Extend CI/CD pipeline:
- Test on Linux, MacOS, and Windows
- Test multiple Python versions (3.9, 3.10, 3.11, 3.12, 3.13)
- Improve documentation

- Add experimental psutil support
- Add server info card for operating system

- Fix rounding down recommended vCPUs with <0.5 load
- Add info popups with more details and disclaimers for recommendations
- Add detection for shared server environments
- Add potential cost savings card
- Improve documentation

Initial PyPI release of `resource-tracker` with the following features:

- Detect if the system is running on a cloud provider, and if so, detect the provider, region, and instance type
- Detect main server hardware (CPU count, memory amount, disk space, GPU count and VRAM amount)
- Track system-wide resource usage:
- Process count
- CPU usage (user + system time, relative vCPU percentage)
- Memory usage (total, free, used, buffers, cached, active anon, inactive anon pages)
- Disk I/O (read and write bytes)
- Disk space usage (total, used, free)
- Network I/O (receive and transmit bytes)
- GPU and VRAM usage (using `nvidia-smi`)
- Track resource usage of a process and its descendant processes:
- Descendant process count
- CPU usage (user + system time, relative vCPU percentage)
- Memory usage (based on proportional set sizes)
- Disk I/O (read and write bytes)
- GPU and VRAM usage (using `nvidia-smi pmon`)
- Add Metaflow plugin for tracking resource usage of a step:
- Track process and system resource usage for the duration of the step
- Generate a card with the resource usage data
- Suggest `resources` decorator for future runs
- Find cheapest cloud instance type for a step