Add unique number ID for each proposal e.g. PROM-1234 or PP-123

[bwplotka]

When developing features it's useful to reference certain proposals and decisions. I propose we start adding unique numbers to each proposal to reference them later.

This is similar to KEP and OTEP numbers.

What about PROM-<number> so it's clear it's a prometheus project proposal?

[ArthurSens]

PEPs? :)

[bwplotka]

PEPSI (prom enha. prop. so interesting)

[roidelapluie]

Would we use the PR ID as number?

[bwplotka]

We absolutely can 👍🏽

Let me try to propose the PR to this repo that updates the process.

We also had amazing discussion here: https://cloud-native.slack.com/archives/C01AUBA4PFE/p1745573021852619

[bwplotka]

Created a quick proposal for this #53