Add support for rpmdb's using sqlite3

There are repeated RFE's to re-add sqlite3 for a rpmdb implementation.

The stated reasons are:
    1) difficulties with Berkeley DB locking
    2) licensing issues with Berkeley DB

The previous implementation worked fine. The weakest point
is that the schema too closely paralleled the existing rpmdb
format, causing these flaws:
    1) SQL statements from bindings could not be used as "expected"
    2) the data normalization was unnatural.

With "RPM ACID" using Berkeley DB 5.x, a better schema which can be
feasibly accessed by any sqlite3 bindings, not just by rpm tools, and'
which can accommodate triggers and foreign keys and lazy table creation
is likely far more feasible.

sqlite3 will be the prototype for designing a schema that can then
be mapped to other SQL database dialects.