Add Eigen in nav2_map_server

[mini-1235]

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Basic Info

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Ticket(s) this addresses	(add tickets here #1)
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Description of contribution in a few bullet points

• I am having build issues when pulling geometry2 and rviz, so I add the eigen3 dependency which is used in map_io.cpp
• Also cleanup some unused related to eigen

Description of documentation updates required from your changes

Description of how this change was tested

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Future work that may be required in bullet points

For Maintainers:

• Check that any new parameters added are updated in docs.nav2.org
• Check that any significant change is added to the migration guide
• Check that any new features OR changes to existing behaviors are reflected in the tuning guide
• Check that any new functions have Doxygen added
• Check that any new features have test coverage
• Check that any new plugins is added to the plugins page
• If BT Node, Additionally: add to BT's XML index of nodes for groot, BT package's readme table, and BT library lists
• Should this be backported to current distributions? If so, tag with backport-*.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
see 12 files with indirect coverage changes

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