Remove encryptDB.php from codebase

Not critical, but I wrote up some thoughts on anonymising DBs today and remembered Eileen offering to merge a PR that removed this file.

I think it should go because:

• It is old and outdated
• We'd be better off rid of scripts in bin/*.php which permit direct access without going through core Civi router
• MD5 is not encryption, so what changes it does make are reversible.
• It targets a limited number of fields, so a DB will contain identifying data even if not deanonymised
• My main concern here is that people might think encryptDB.php really encrypts your DB.

See also:

• http://civicrm.stackexchange.com/questions/17898/how-would-you-anonymise-private-data-for-developer-stage
• https://github.com/xurizaemon/org.civicrm.contrib.anonymize/blob/obfuscate_db/obfuscate_db.php (slightly improved version, which I'm not submitting for inclusion here)