Properly handle Base64-encoded attributes

[maxbes]

Currently, if I use ExecutableLdifSourceService with a LDIF that contains base64-encoded fields, the attributes will show up incorrectly in LSC:

(actual value: Cécile)

ldif:

givenName:: Q8OpY2lsZQ==

in LSC the value appears, literaly, as :

0x43 0xC3 0xA9 0x63 0x69 0x6C 0x65

This MR fixes the conversion from o.a.d.api.ldap.model.entry.Value to java.lang.String so that Values that were decoded from Base64 no longer appear as a string of hex codes.

⚠️ possible regressions: pure binary data (jpegPhoto) that appears in a LDIF file will also be exposed to LSC as pure binary data from now on

[elecharny]

A very bad usage of the Value.toString() method, indeed. The fix is valid, calling the Value.getString() method will return the proper string:

• If the value is HR, the returned value will be the User Provided value (ie the not normalized string)
• If the value is binary, it will return a String representation of the binary content, assuming it's UTF8 encoded.