[CT-3369] [implementation] new test types for unit tests and data tests in dbt test command

[graciegoheen]

Housekeeping

• I am a maintainer of dbt-core

Short description

From #8606 and #8651:

unit tests and data tests are types of tests that can be selected using --select test_type:unit or --select test_type:data for dbt build, dbt test, and dbt list.

issue for dbt list -> #8508
issue for dbt build -> #8979

Acceptance criteria

dbt test --select test_type:unit -> runs only your unit tests
dbt test --select test_type:data -> runs only your data tests
dbt test -> runs all of your tests (both unit and data)

Note: test_type:generic and test_type:singular remain as is (they're just documented as subsets of data tests)

Impact to Other Teams

none

Will backports be required?

no

Context

No response