Tpetra: Make CrsGraph MatrixMarket I/O memory scalable

[mhoemmen]

@trilinos/tpetra
Epic: #769

MatrixMarket input and output (I/O) for Tpetra::CrsGraph currently gathers the whole matrix to Process 0 before writing it. This is not memory scalable. "Memory scalable" means that no single process has to store more than a small constant factor times the maximum per-process memory usage of the distributed data structure. See also #352 and #353.

[kddevin]

#7045 begins to address this issue

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[github-actions]

This issue has had no activity for 365 days and is marked for closure. It will be closed after an additional 30 days of inactivity.
If you would like to keep this issue open please add a comment and/or remove the MARKED_FOR_CLOSURE label.
If this issue should be kept open even with no activity beyond the time limits you can add the label DO_NOT_AUTOCLOSE.
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[mhoemmen]

autobot begone

[github-actions]

This issue has had no activity for 365 days and is marked for closure. It will be closed after an additional 30 days of inactivity.
If you would like to keep this issue open please add a comment and/or remove the MARKED_FOR_CLOSURE label.
If this issue should be kept open even with no activity beyond the time limits you can add the label DO_NOT_AUTOCLOSE.
If it is ok for this issue to be closed, feel free to go ahead and close it. Please do not add any comments or change any labels or otherwise touch this issue unless your intention is to reset the inactivity counter for an additional year.

[GrahamBenHarper]

this sounds important to not close. begone bot