Increase VARCHAR limits and impose String length validation

[rymaju]

Most of our SQL errors are errors with VARCHAR string lengths in our SQL schemas not being validated in our DTOs, we should add those string length checks on the DTO level for more informative error messages or not set a VARCHAR limit at all.

(This is a duplicate of the LLB ticket)

• Increase arbitrarily low VARCHAR limits to 255
• Validate all strings to match the limits we impose in the schema