Define database offering pricing/packaging

### Description

With the investment into FlowFuse offering it's own database offering, we need to define and scope the packaging of the service.

We plan to start with a Timeseries offering: https://github.com/FlowFuse/flowfuse/issues/5594

### Pricing

- How do we price the database offering?
- Limits on table numbers
- Throughout? Reads/Writes?
- Which tiers do we make it available to?

Comparison: [Prisma.io](https://www.prisma.io/pricing)

### Epic/Story

https://github.com/FlowFuse/flowfuse/issues/4911

### Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate