Increase maxium amount of log block

[ataffanel]

Currently the log subsystem is setup to accept 8 log block maximum. The latest development versions of the client starts exactly 8 log block at startup which prevent starting any more for plotting for example. Since we have more than enough memory in Crazyflie 2.0 we should increase the maximum allowed log block. For Crazyflie 1.0 the client will not start that much log block since the additional blocks are needed by the loco positioning tab.