feat(coderd): add support for presets to the coder API (#16526)

This pull request builds on the existing migrations and queries to add
support for presets to the coder API.

codersdk/presets.go

@@ -0,0 +1,36 @@
+package codersdk
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+
+	"github.com/google/uuid"
+	"golang.org/x/xerrors"
+)
+
+type Preset struct {
+	ID         uuid.UUID
+	Name       string
+	Parameters []PresetParameter
+}
+
+type PresetParameter struct {
+	Name  string
+	Value string
+}
+
+// TemplateVersionPresets returns the presets associated with a template version.
+func (c *Client) TemplateVersionPresets(ctx context.Context, templateVersionID uuid.UUID) ([]Preset, error) {
+	res, err := c.Request(ctx, http.MethodGet, fmt.Sprintf("/api/v2/templateversions/%s/presets", templateVersionID), nil)
+	if err != nil {
+		return nil, xerrors.Errorf("do request: %w", err)
+	}
+	defer res.Body.Close()
+	if res.StatusCode != http.StatusOK {
+		return nil, ReadBodyAsError(res)
+	}
+	var presets []Preset
+	return presets, json.NewDecoder(res.Body).Decode(&presets)
+}