Move images from `Plots.jl` to `Makie.jl` + `AlgebraOfGraphics.jl`

[storopoli]

Code to replace:

• Densities in 2_bayes_stats.jl: straight up drop-in from Plots.jl to Makie.jl
• PMFs/PDFs in 3_prob_dist.jl: straight up drop-in from Plots.jl to Makie.jl
• Visualizations in 4_Turing.jl: use David's suggestions in Rewriting MCMCChains with Makie.jl+AlgebraOfGraphics TuringLang/MCMCChains.jl#306 (comment)
• Animations in 5_MCMC.jl: don't know, first foray into Makie.jl animations.
• Densities in 7_logistic_reg.jl, 8_count_reg.jl and 9_robust_reg.jl: straight up drop-in from Plots.jl to Makie.jl
• Funnel in 11_Turing_tricks.jl: straight up drop-in from Plots.jl to Makie.jl
• Time Series and ODE Solution in 12_epi_models.jl: straight up drop-in from Plots.jl to Makie.jl