Use code generation from GNSSSignals.jl

[dominformant]

The tracking of BOC-Signals requires to load the code with non-integer phases to enable the subcarrier generation.
Using FixedPointNumbers.jl gives comparable speed as the current implementation while providing the fractional phase in the code access.

[zsoerenm]

I have added CI for all new pull request right here on Github. There are still some errors (see below).

[dominformant]

Actually, the code generation can simplified here, as soon as JuliaGNSS/GNSSSignals.jl#21 is merged.

[codecov-commenter]

Codecov Report

Merging #29 (95d2e7a) into master (379c19f) will decrease coverage by 1.71%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #29      +/-   ##
==========================================
- Coverage   90.97%   89.26%   -1.72%     
==========================================
  Files          16       16              
  Lines         432      419      -13     
==========================================
- Hits          393      374      -19     
- Misses         39       45       +6     

Impacted Files	Coverage Δ
src/code_replica.jl	100.00% <100.00%> (ø)
src/downconvert.jl	52.94% <0.00%> (-8.83%)	⬇️
src/Tracking.jl	100.00% <0.00%> (ø)

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[zsoerenm]

The test is failing because the minimal Julia version that is required by the new GNSSSignals.jl is v1.6
So I guess Project.toml and .github/workflows/ci.yml need to reflect this change

[dominformant]

Code generation is now implemented by GNSSSignals.jl to enhance code reuse. Minimum Julia version is increased to 1.6 as required by GNSSSignals.jl.