Handle errors during requests

[Kaptard]

Right now, if an error occurs on either the API or Core node, it simply doesn't respond. Instead, we should put a try/catch around it on both the API and Core node, and return the error in plaintext in development, or encrypted in production.

[Kaptard]

Updated a while ago to save the errors in the API's database (cubic-errors collection). Still requires sending the errors in the formats mentioned.