Add support for date parameter for `analytics` queries

[mre]

Example: http://localhost/analytics/v1/podcastGender?date=2023-02-12

[woolfg]

I would suggest to add start/end as params to be more flexible. the user can then decide if just one day is needed or a range should be fetched from the API

[mre]

tackling this next

[woolfg]

could we use markdown/yaml/frontmatter/json to define the SQL queries and metadata? would be the advantage that we do not have to invent our own format?

[mre]

I think we can. Let's introduce the date parameters manually first and then consider rewriting it to dbt. I have a feeling that it will simplify things a lot.

[mre]

We decided that we'll try to use SQL variables, which are a nice tradeoff between customizability and fully native SQL syntax.

[woolfg]

in progress openpodcast/api#67