Implement read-only mode

[sudokoko]

This PR implements the ability to put an instance in a "read-only" state.

The following actions are limited or disabled while in read-only mode:

• Level uploads or changes
• Photo uploads
• General asset uploads (/upload/hash)
• Profile picture/biography changes
• Post/delete comments
• Post/delete reviews

A message will also be appended to the base website layout, as well as the /announce endpoint.

This could probably be refactored into a simple middleware or something in the future.

[Slendy]

Some small feedback about returning 400 on the website page. You also need to add checks in SlotSettingsPage and protect the calls to ParseBase64Image

[Zaprit]

Looks good, however do you think it would be worth while having some additional information field in there, so we can link to the blog post?

[sudokoko]

Looks good, however do you think it would be worth while having some additional information field in there, so we can link to the blog post?

I think that might be a bit too specific to our case, though feel free to object. An instance administrator can always link to it in the announcement config and create a web based announcement.

[HenryAsbridge]

specific

I suspect that anyone who's putting their lighthouse instance into read only mode is doing so for a reason, and may want to communicate with their users as to why

[Zaprit]

specific

I suspect that anyone who's putting their lighthouse instance into read only mode is doing so for a reason, and may want to communicate with their users as to why

and this is why you don't use the github mobile app, because it will make you respond on your work account smh. why can't it use the account that's in the org where the PR is, rather than the wrong account at the wrong time

[sudokoko]

specific

I suspect that anyone who's putting their lighthouse instance into read only mode is doing so for a reason, and may want to communicate with their users as to why

#1001 (comment)

An instance administrator can always link to it in the announcement config and create a web based announcement.

I may just be OCD, but I feel like implementing a dedicated configuration option for something that can be done through existing config options (announceText) and website features (web announcements, which will be implemented into the game as well through #855) is a bit redundant. Though if this is something you wholeheartedly believe should be implemented, I will do so. Just thought I'd voice my concern on it before doing that.

[Zaprit]

specific

I suspect that anyone who's putting their lighthouse instance into read only mode is doing so for a reason, and may want to communicate with their users as to why

#1001 (comment)

An instance administrator can always link to it in the announcement config and create a web based announcement.

I may just be OCD, but I feel like implementing a dedicated configuration option for something that can be done through existing config options (announceText) and website features (web announcements, which will be implemented into the game as well through #855) is a bit redundant. Though if this is something you wholeheartedly believe should be implemented, I will do so. Just thought I'd voice my concern on it before doing that.

I suppose the important part is do our banner announcements show up front and centre on the home page of the instance in a way that doesn't require you to go digging?

[sudokoko]

I suppose the important part is do our banner announcements show up front and centre on the home page of the instance in a way that doesn't require you to go digging?

No, however I would not be opposed to implementing this, and would actually prefer doing it this way. I would probably just package those changes in with this PR since they are technically in scope.

[Slendy]

Only issue is returning a 400 status code on the website instead of redirecting back to the original page to stay consistent with the rest of the website.