Convert AMR102 and Pachinko to Guided Tutorials#31

Draft

etpalmer63 wants to merge 4 commits intoAMReX-Codes:mainfrom etpalmer63:advect_part_obstacles

+808

Commits on Sep 7, 2021

Need to explain what "subcycling-in-time" is in this context.
etpalmer63
committed

Commits on Sep 10, 2021

Converting AMReX 102 to Guided Tutorial.
etpalmer63
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More formatting for change to rst type.
etpalmer63
committed

Commits on Sep 15, 2021

Add images, previously untracked.
etpalmer63
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