Make plotting functionality an extension package

[jack-champagne]

IMPORTANT

Current implementation means conflicting global symbols exported from Makie/MakieCore/CairoMakie - specifically "plot".

We must either:
a) change all namedtrajectories plot calls to use path plot -> NamedTrajectories.plot
b) change the symbol name in NamedTrajectories plot -> nm_plot
c) use extension package to register a recipe within Makie to continue to use their symbol plot

[codecov]

Codecov Report

Attention: Patch coverage is 40.95238% with 62 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
ext/NamedTrajectoryCairoMakieExt.jl	40.95%	62 Missing ⚠️

Files with missing lines	Coverage Δ
ext/NamedTrajectoryCairoMakieExt.jl	40.95% <40.95%> (ø)

[andgoldschmidt]

(c) use extension package to register a recipe within Makie to continue to use their symbol plot

It looks like Makie.convert_arguments with PointBased might be one nice way to accomplish this?

Especially if we want the least overhead, because it seems like we could even get away with MakieCore.