Galileo e5a

New files (all include e5a within the name):
New E5a signal processing blocks, adapters and libraries.

Modified existing files:
- CMake lists
- Block factory and flowgraph to accomodate new blocks
- Signal generator to accomodate e5a
- In 2nd order DLL/PLL, full z transform formula was implemented giving identical results to the previous existing one (optional merge). However, the function that enables integration time change ('set_pdi') must be merged in master.
- In src/algorithm/tracking/libs/correlator was accomodated a correlator that keeps track of pilot signal while decoding also navigation (data) bits.
- In src/algorithms/telemetry_decoder/libs/convolutional.h, an existing function was declared as static so that it can be used also for e5a with no compilation errors (it is legal since this function is only called from the same source file).