Create user bitmaps

[piconti]

Prepare the code that creates user bitmaps and performs the AND operations in the impresso middle layer.

• The user status and institution keys of the bitmaps are available here
• A specific table on the MySQL DB needs to be created to store the bitmaps
• Functions performing the AND operations need to be implemented.
• Item bits will be accessible from Solr once ingested.

The four first bits (starting on the left, indices 0-3) are the ones relating to the user plans
The user bitmap relating to user plans is cumulative, hence, any user that is a researcher (bit #3 = 1) has all preceeding bits also set to 1 : 1111 [archive bits...].
All users have at least the "guest" bit set to 1 (bit #1): 1000 [archive bits, all 0]

[piconti]

Here is the bitwise and function I implemented for the bitmaps.