boiler model boundary conditions have separate speeds for different throttles and possibility of increasing speed

mended AUSM+ diff. operator

added solver containing Steger-Warming, Van Leer and Lax Friedrich in one for Euler and Navier-Stokes

Documentation: fixed branch name for CI builds

See merge request !40

CI: deploy with artifacts

See merge request !39

Setup for automatic documentation deployment

See merge request !38

Reduction and multireduction refactoring

Brief summary:

- rewritten multireduction using lambda functions
- avoided `volatile` using `__syncwarp()`
- using reduction functions with `return a + b` instead of `a += b`
- using `std::plus`, `std::multiplies`, `std::logical_and`, `std::logical_or`, etc. instead of custom lambda functions
- optimized OpenMP thread counts for reduction and multireduction
- added computation of sample standard deviation to benchmarks
- implemented parallel prefix-sum with OpenMP
- implemented distributed prefix-sum

See merge request !37

Fixes #43

PrefixSum: separate first and second phase for OpenMP implementation and expose performFirstPhase and performSecondPhase methods