lazily load feature packages

[johnnychen94]

Lazily load ImageCore and ImageInTerminal using my newly written tool LazyModules.jl

This cuts the package loading latency from

julia> @time_imports using ReferenceTests
      0.6 ms    ┌ Compat
      0.4 ms    ┌ NaNMath
      0.3 ms      ┌ Adapt
     33.8 ms      ┌ OffsetArrays
     35.5 ms    ┌ PaddedViews
     20.6 ms    ┌ FixedPointNumbers
     42.5 ms      ┌ ChainRulesCore
     43.4 ms    ┌ ChangesOfVariables
      5.3 ms    ┌ AbstractFFTs
      0.3 ms    ┌ OpenLibm_jll
      1.4 ms      ┌ StackViews
      2.0 ms      ┌ MappedArrays
      4.3 ms    ┌ MosaicViews
      0.5 ms    ┌ InverseFunctions
      0.1 ms    ┌ Reexport
      4.3 ms    ┌ DocStringExtensions 68.85% compilation time
     98.8 ms      ┌ ColorTypes 4.71% compilation time
     84.2 ms      ┌ Colors
    185.2 ms    ┌ Graphics 2.51% compilation time
      3.1 ms    ┌ IrrationalConstants
      0.4 ms    ┌ TensorCore
      0.7 ms      ┌ LogExpFunctions
     14.4 ms          ┌ Preferences
     15.0 ms        ┌ JLLWrappers
    143.5 ms      ┌ OpenSpecFun_jll 89.07% compilation time (98% recompilation)
    174.3 ms    ┌ SpecialFunctions 73.33% compilation time (98% recompilation)
     87.4 ms    ┌ ColorVectorSpace 5.54% compilation time
    811.2 ms  ┌ ImageCore 18.82% compilation time (82% recompilation)
      0.4 ms  ┌ Requires
      0.3 ms    ┌ StatsAPI
      4.4 ms  ┌ Distances
     24.5 ms    ┌ Crayons
     30.8 ms    ┌ ImageBase
     90.2 ms  ┌ ImageInTerminal 11.81% compilation time (16% recompilation)
      2.7 ms  ┌ DeepDiffs
     72.4 ms  ┌ FileIO 8.02% compilation time
   1042.8 ms  ReferenceTests 16.22% compilation time (75% recompilation)

to

julia> @time_imports using ReferenceTests
      0.8 ms  ┌ LazyModules
      0.4 ms  ┌ Requires
      0.5 ms    ┌ StatsAPI
      3.4 ms  ┌ Distances
     22.6 ms  ┌ FixedPointNumbers
      0.2 ms  ┌ Reexport
      1.3 ms  ┌ DeepDiffs
     68.3 ms  ┌ FileIO 10.21% compilation time (21% recompilation)
     94.6 ms  ┌ ColorTypes 4.88% compilation time
     60.3 ms  ┌ Colors
    332.7 ms  ReferenceTests 6.82% compilation time (7% recompilation)

The caveats is world-age issues due to the dynamic lazy loading, thus a world-age issue test is added. Hopefully, it catches the issue in the long run.

The test time time julia-latest --startup=no --project=. -e 'using Pkg; Pkg.test()' is still ~35s