Currently, the majority of the configurable options for commands (like maintenanceMode, supportsRetryableWrite, allowedWithSecurityToken, etc.) are implemented via non-constexpr virtual functions on the base `Command` class. If we moved these options to the IDL specs of the commands themselves, this would:

1) make the options for each command less verbose and easier to grep for. Compare:

virtual bool adminOnly() {
  return false;
}

to

adminOnly: false

2) heavily improve our ability to do static analysis on the set of all our commands, allowing us to easily compile a list of all commands and their options and documentation, which we can present to both developers and end-users
3) allow us to document and enforce constraints on commands at build time, such as `(!command->requiresAuth() && command->allowedInTransactions()` being a contradiction.