[Feature request] Allow users to manually change the security level in the FE or hide features that are not allowed in the current security level config.

When users install custom nodes and choose the nightly version, they will install the custom nodes from GitHub. However, since the default `security_level` is set to `normal`, users may be confused as to why they can't install custom nodes.

Also, there is too little information in the prompt. Users who don't know how to change the security_level setting will only feel frustrated.

Here's my advice

## 1. Only show interface features allowed by the user's current security settings.

Such as hide the "nightly version" or don't use the "nightly" as default version (but seems lot of custom node only have nightly)

Don't show the `install PIP package` and `install via Git URL` if their `security_level` isn't weak.

Otherwise, when users try to use these features for the first time, they will be confused about why they can't install custom nodes.

## 2. Allow users change the `security level` in the FE

I think a lot of users still look up how to fix security level issues every day. Whatever the outcome, they always set the security to 'weak' once they figure out how.

So why not allow users to change security settings in the FE? But we should make sure users fully understand the consequences and risks. Add more details in the prompt, then let users decide whether to change the settings or not.

Especially for beginners, they may not know much about computers or ComfyUI. Sometimes they might not even know how to update the config.ini

## 3. Add more details in the prompt.

The current prompt lacks information. Should we add more details to tell users how they can change the security settings?

Such as "This action is not allowed with this security level configuration. If you need to, you can change the `security level` to `weak` in the `ComfyUI/user/default/ComfyUI-Manager/config.ini`. [Notice] Please make sure you know what it means, otherwise you shouldn't change this setting."