Implementing fuzzing got things moving and #466 surfaced some problems regarding the v3 directory:

• The oldest supported version is Go 1.14, which already had Go Module integration
• The root and v3 directory have been out of sync multiple times, including missing public variables/functions/documentation
• People have to decide whether they use "github.com/go-ldap/ldap" or "github.com/go-ldap/ldap/v3" and maybe accidently include both in their codebase.

Since #367, we can't support older versions anyways as they're missing the necessary struct fields, meaning all versions used afterwards have Go modules integrated, which in turn means that there should be little to no breaking changes when dropping/stop mirroring the v3 directory. But, this would mean that programs >Go 1.14 which have the v3 directory imported need to be updated.

I want to start an open discussion about stopping mirroring the code. Any opinions are welcome.