Adds the --select and --exclude arguments to the sqlmesh_dbt run and sqlmesh_dbt list commands (the list command is mainly for testing expressions).

This is implemented in terms of generating a complex selection targeting the SQLMesh selector engine rather than attempting to re-implement a new selector engine from scratch.

• dbt set unions eg model_a model_b are translated to |
• dbt set intersections eg model_a,model_b are translated to &
• --exclude is implemented in terms of using negation ^ on each expression and then doing a set intersection with whatever was supplied for --select

The selectors are still matched against model names, which differ between dbt and sqlmesh.

For example, on jaffle shop, the following selector works in dbt:
dbt list --select customers (selects the jaffle_shop.customers model)

However, on the SQLMesh selector engine it will return nothing, it needs to be:
sqlmesh_dbt list --select main.customers

I intend to address this in a follow-up PR if the groundwork laid in this PR is considered a suitable direction