Build models for engineering team metrics

[clrcrl]

Description and motivation

These models will be used for dashboards on engineering team velocity

Validation

Here's the query:

select
    date_trunc(merged_at, week)  as date_week,
    type,
    count(*) as number_of_prs,
    avg(days_open_to_merge) as avg_days_open_to_merge
from `graceful-creek-264520.dbt_claire.pull_requests`
where merged_at is not null
group by 1, 2
order by 1 desc