Go safe SQL implementation

In order to use this library the following steps must be taken:

• Set up your CI/tests so that you can:
  • Ban imports of a specific package/function
  • Create an allowlist of call sites that can use that package/function
• Create an atomic change that:
  • Converts all calls to database/sql into calls to safesql. This can easily be achieved with the legacyconversions package and automated patching.
  • Prevents new calls to legacyconversions from being added and bans import of the database/sql package. This should ideally be true for all transitive dependencies.
  • Only allows safesql to import database/sql.
• After submitting that change, gradually migrate legacyconversions calls to use safesql functions or be promoted to uncheckedconversions. If you chose the latter make sure the strings that you promote are controlled by the programmer and never by the user.