Cocoon should expose lab constraints

### Type of Request

feature request

### Infrastructure Environment

Cocoon

### What is happening?

Every few weeks we do a song and dance of people needing to get together to figure out what the current lab constraints are, and what are upgrade path will look like going forward.

I suggest we automate some of the work, and have Cocoon generate a lab constraint matrix based on `.ci.yaml`. The workflow would look like:

1. Collect ci.yamls for master, stable, beta, and the oldest 30 day RC branch (to support Google's CPs) and for engine+flutter repos
2. For each platform, collect dimensions and create a min and max, and output them in a matrix

For example:

| Dimension | Min | Max | Constraint |
|-------------------|-----|-----|--------------------------|
| mac_os | 13 | 13 | |
| mac_ios_device_os | 15 | 16 | flutter-3.19-candidate.1 |

A common matrix would help the lab know what can be upgraded.

A future feature request would be to take this data, and compare it to our swarming fleet so we can get the answer to questions like "are there optimizations we can be making"?

I propose adding this to Cocoon for now as the server already knows how to work with release ci.yamls, and we can quickly add constraint logic to a request handler.

### Steps to reproduce

N/A

### Expected results

I expect to see X when Y is finished.