Define objective bridge and objective map

[blegat]

Extracted from #789

[codecov-io]

Codecov Report

Merging #867 into master will decrease coverage by 0.22%.
The diff coverage is 42.85%.

@@            Coverage Diff             @@
##           master     #867      +/-   ##
==========================================
- Coverage   94.97%   94.74%   -0.23%     
==========================================
  Files          73       76       +3     
  Lines        7999     8034      +35     
==========================================
+ Hits         7597     7612      +15     
- Misses        402      422      +20

Impacted Files	Coverage Δ
src/Bridges/bridge.jl	75% <ø> (ø)	⬆️
src/Bridges/Bridges.jl	100% <ø> (ø)	⬆️
src/Bridges/Objective/bridge.jl	0% <0%> (ø)
src/Bridges/Objective/Objective.jl	100% <100%> (ø)
src/Bridges/Objective/map.jl	58.33% <58.33%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a510666...1944d10. Read the comment docs.