chore: Rename Projects to Templates (#880)

Customer feedback indicated projects was a confusing name.
After querying the team internally, it seemed unanimous
that it is indeed a confusing name.

Here's for a lil less confusion @ashmeer7 🥂

coderd/httpmw/templateparam.go

@@ -0,0 +1,53 @@
+package httpmw
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"net/http"
+
+	"github.com/go-chi/chi/v5"
+
+	"github.com/coder/coder/coderd/database"
+	"github.com/coder/coder/coderd/httpapi"
+)
+
+type templateParamContextKey struct{}
+
+// TemplateParam returns the template from the ExtractTemplateParam handler.
+func TemplateParam(r *http.Request) database.Template {
+	template, ok := r.Context().Value(templateParamContextKey{}).(database.Template)
+	if !ok {
+		panic("developer error: template param middleware not provided")
+	}
+	return template
+}
+
+// ExtractTemplateParam grabs a template from the "template" URL parameter.
+func ExtractTemplateParam(db database.Store) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+			templateID, parsed := parseUUID(rw, r, "template")
+			if !parsed {
+				return
+			}
+			template, err := db.GetTemplateByID(r.Context(), templateID)
+			if errors.Is(err, sql.ErrNoRows) {
+				httpapi.Write(rw, http.StatusNotFound, httpapi.Response{
+					Message: fmt.Sprintf("template %q does not exist", templateID),
+				})
+			}
+			if err != nil {
+				httpapi.Write(rw, http.StatusInternalServerError, httpapi.Response{
+					Message: fmt.Sprintf("get template: %s", err),
+				})
+				return
+			}
+
+			ctx := context.WithValue(r.Context(), templateParamContextKey{}, template)
+			chi.RouteContext(ctx).URLParams.Add("organization", template.OrganizationID.String())
+			next.ServeHTTP(rw, r.WithContext(ctx))
+		})
+	}
+}