Clean the using in each subpackage

[ErikQQY]

The current way of using packages is messy, so this PR cleans these files and did some refactoring

[github-actions]

Benchmark Results

	master	c5a4c28...	master/c5a4c28ecdbaaa...
Simple Pendulum/IIP/BoundaryValueDiffEqMIRK.MIRK2()	6.82 ± 0.31 ms	6.82 ± 0.18 ms	1
Simple Pendulum/IIP/BoundaryValueDiffEqMIRK.MIRK3()	2.64 ± 0.14 ms	2.61 ± 0.11 ms	1.01
Simple Pendulum/IIP/BoundaryValueDiffEqMIRK.MIRK4()	0.951 ± 0.053 ms	0.938 ± 0.051 ms	1.01
Simple Pendulum/IIP/BoundaryValueDiffEqMIRK.MIRK5()	2.53 ± 0.42 ms	2.47 ± 0.23 ms	1.02
Simple Pendulum/IIP/BoundaryValueDiffEqMIRK.MIRK6()	1.12 ± 0.11 ms	1.09 ± 0.072 ms	1.02
Simple Pendulum/IIP/MultipleShooting(10, Tsit5; grid_coarsening = false)	2 ± 0.59 ms	1.91 ± 0.6 ms	1.04
Simple Pendulum/IIP/MultipleShooting(10, Tsit5; grid_coarsening = true)	3.63 ± 0.91 ms	3.52 ± 0.87 ms	1.03
Simple Pendulum/IIP/MultipleShooting(100, Tsit5; grid_coarsening = false)	0.0545 ± 0.009 s	0.0525 ± 0.007 s	1.04
Simple Pendulum/IIP/MultipleShooting(100, Tsit5; grid_coarsening = true)	0.0671 ± 0.0087 s	0.0656 ± 0.016 s	1.02
Simple Pendulum/IIP/Shooting(Tsit5())	0.249 ± 0.079 ms	0.246 ± 0.078 ms	1.01
Simple Pendulum/OOP/BoundaryValueDiffEqMIRK.MIRK2()	0.0391 ± 0.0012 s	0.0384 ± 0.0012 s	1.02
Simple Pendulum/OOP/BoundaryValueDiffEqMIRK.MIRK3()	11.5 ± 0.43 ms	11.3 ± 0.26 ms	1.02
Simple Pendulum/OOP/BoundaryValueDiffEqMIRK.MIRK4()	3.35 ± 0.21 ms	3.33 ± 0.23 ms	1.01
Simple Pendulum/OOP/BoundaryValueDiffEqMIRK.MIRK5()	9.82 ± 0.89 ms	9.87 ± 0.9 ms	0.995
Simple Pendulum/OOP/BoundaryValueDiffEqMIRK.MIRK6()	3.59 ± 0.3 ms	3.58 ± 0.31 ms	1
Simple Pendulum/OOP/MultipleShooting(10, Tsit5; grid_coarsening = false)	3.47 ± 2.6 ms	3.35 ± 2.6 ms	1.04
Simple Pendulum/OOP/MultipleShooting(10, Tsit5; grid_coarsening = true)	6.2 ± 4.3 ms	5.91 ± 4.3 ms	1.05
Simple Pendulum/OOP/MultipleShooting(100, Tsit5; grid_coarsening = false)	0.105 ± 0.0077 s	0.0954 ± 0.003 s	1.1
Simple Pendulum/OOP/MultipleShooting(100, Tsit5; grid_coarsening = true)	0.127 ± 0.011 s	0.116 ± 0.009 s	1.09
Simple Pendulum/OOP/Shooting(Tsit5())	0.615 ± 0.049 ms	0.623 ± 0.043 ms	0.987
time_to_load	7.99 ± 0.19 s	7.73 ± 0.022 s	1.03

Benchmark Plots

A plot of the benchmark results have been uploaded as an artifact to the workflow run for this PR.
Go to "Actions"->"Benchmark a pull request"->[the most recent run]->"Artifacts" (at the bottom).

[ErikQQY]

The failing BVPM2 wrapper tests are commented out to not impediment the other tests, and the wrapper solvers will be switched to BVPInterface.jl(specialized interface package for Fortran BVP solvers) once it's registered