[Feature] Ability to set initial accumulated plastic strain

[mitchellmcm27]

I want to add the ability to set the initial APS, similar to how we can set the initial temperature and phases on the domain. Although pretty simple, this feature involves coordinated PRs in LaMEM, LaMEM.jl and GeophysicalModelGenerator.jl (see below). The changes are meant to be fully backwards compatible. I am leaving this as a draft as I want to get some feedback on the approach.

For more details, see the PR in the LaMEM repo (UniMainzGeo/LaMEM#41)

Summary of changes

LaMEM.jl (this PR)

• adds APS as a property of Grid and passes it to CartData
• adds ability to plot plast_strain as a cross-section (name matches Paraview field)
• adds out_ptr_APS option to include APS on passive tracers (defaults to 0)

GeophysicalModelGenerator.jl (JuliaGeodynamics/GeophysicalModelGenerator.jl#184)

• writes APS from Grid as an additional property in the marker binary file (defaults to 0 if not given)
• increments the file header to enable backwards compatibility

LaMEM (UniMainzGeo/LaMEM#41)

• sets initial APS, if present, from marker binary file
• interprets the file header (previously ignored) as a version number to maintain backwards compatibility
• outputs APS as a field on markers
• optionally outputs APS as a field on passive tracers (defaults to no APS output)
• confirmed all tests pass locally