Use richer `previewtypes.Parameter` for `wsbuilder`. This is a pre-requirement to adding dynamic parameter validation.

The richer type contains more information than the `db` parameter, so the conversion is lossless.

Using the db.Store when in a TX causes a deadlock for dbmem.
In production, this can cause a deadlock if at the current conn pool
limit.

Parallel concurrent queries cannot be run in the same tx

Was getting this error: https://stackoverflow.com/questions/78472996/go-postgres-pq-unexpected-parse-response-c-with-queryrow

# What does this do?

This does parameter validation for dynamic parameters in `wsbuilder`. All input parameters are validated in `coder/coder` before being sent to terraform.

The heart of this PR is [`ResolveParameters`](https://github.com/coder/coder/blob/b65001e89c0577199a8e470c138c51e91cf2350c/coderd/dynamicparameters/resolver.go#L30-L30).

# What else changes?

`wsbuilder` now needs to load the terraform files into memory to succeed. This does add a larger memory requirement to workspace builds.

# Future work

- Sort autostart handling workspaces by template version id. So workspaces with the same template version only load the terraform files once from the db, and store them in the cache.

)

resolves coder/preview#58

…ate (#18505)

When in experimental this was used as an escape hatch. Removed to be
consistent with the template author's intentions

Backwards compatible, removing an experimental api field that is no longer used.

`BuildError` response from `wsbuilder` does not support rich errors from validation. Changed this to use the `Validations` block of codersdk responses to return all errors for invalid parameters.