Cloud provider validation for self-hosting (suggest new providers in comments)

- [x] DigitalOcean
- [ ] Linode
- [ ] PikaPods
- [ ] Vultr

While in theory all cloud providers should work... there are several real world factors that limit their viability. For example, only having servers in EU/US, or having soft/hard limit on network throughput, allowance to enable uncommon ports and many more.

In this thread we will discuss the viability of the aforementioned providers, and reflect on whether they're recommended or not. A provider not having a checkmark doesn't mean they can't run `xplex` - it means we haven't validated it to be a recommended option. Specifics for each will be posted in the threads below.