feat(security): Implement Bcrypt for basic auth and deprecate SHA512

I've re-written the code for this several times before but always ended up not going through with it because a hashed Bcrypt string has dollar signs in it, which caused issues with the config due to environment variable support.
I finally decided to go through with it by forcing users to base64 encode the bcrypt hash

security/sha512.go

@@ -6,6 +6,7 @@ import (
 )
 
 // Sha512 hashes a provided string using SHA512 and returns the resulting hash as a string
+// Deprecated: Use bcrypt instead
 func Sha512(s string) string {
 	hash := sha512.New()
 	hash.Write([]byte(s))