Add extra validation for user-submitted data

[dankmeme01]

• Avoid unzipping zip bombs (skip processing entirely if total uncompressed size >= 512mb)
• Cap sizes of mod.json and markdown files
• Validate that mod name consists of only printable characters
• Put reasonable length limits on a bunch of strings
• Add length limit to dev display names

[Fleeym]

Hi, just a few nitpicks for this.

[dankmeme01]

Implemented better errors for client, for example:

• ID too long: Invalid mod.json: validation error: field 'id' is invalid: length must be at most 64 characters
• Name too long: Invalid mod.json: validation error: field 'name' is invalid: length must be at most 256 characters
• Tags too long: Invalid mod.json: validation error: field 'tags' is invalid: String is too long (max 256 characters)