Add Migrations for Role and Permission Set management

This commit introduces database schema changes to extend the role and
permission management capabilities of Solidus.
These changes are derived from the solidus_user_roles gem and are
designed to provide more granular control over user roles and permissions.

Changes include:
  * Create Spree Permission Sets:
      Introduced a new Spree::PermissionSet table in the database.
      This table will store sets of permissions, each with a name and set
      identifier, that can be assigned to user roles.

  * Create Spree Roles Permissions:
      Introduced a new Spree::RolePermission table in the database.
      This table will store the associations between roles and permission sets.
      It includes foreign key references to the Spree::Role and
      Spree::PermissionSet tables.

core/db/migrate/20230607100048_create_spree_permission_sets.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class CreateSpreePermissionSets < ActiveRecord::Migration[7.0]
+  def change
+    create_table :spree_permission_sets do |t|
+      t.string :name
+      t.string :set
+      t.timestamps
+    end
+  end
+end

core/db/migrate/20230607100109_create_spree_roles_permissions.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+class CreateSpreeRolesPermissions < ActiveRecord::Migration[7.0]
+  def change
+    create_table :spree_role_permissions do |t|
+      t.references :role
+      t.references :permission_set
+      t.timestamps
+    end
+  end
+end