new lattice2dboundary element and latticedamage material

[githubgrasp]

1. Introduce new lattice element for 2d periodic cells.
   Added test and manual description.

2. Replaced latticedamage2d with latticedamage which will work for 1d, 2D and 3D lattice elements.
   Modified manual entry and test accordingly.

[codecov]

Codecov Report

Merging #54 into master will increase coverage by 0.46%.
The diff coverage is 72.88%.

@@            Coverage Diff             @@
##           master      #54      +/-   ##
==========================================
+ Coverage   36.72%   37.18%   +0.46%     
==========================================
  Files        1177     1185       +8     
  Lines      120447   121647    +1200     
==========================================
+ Hits        44229    45231    +1002     
- Misses      76218    76416     +198

Impacted Files	Coverage Δ
src/sm/Elements/lattice2d.h	11.11% <ø> (ø)	⬆️
src/sm/Elements/lattice2d.C	64% <ø> (+5.95%)	⬆️
src/sm/Elements/latticestructuralelement.h	0% <0%> (ø)	⬆️
src/sm/Materials/structuralmaterial.h	7.69% <0%> (-2.31%)	⬇️
src/sm/Materials/latticelinearelastic.h	12.5% <12.5%> (ø)
src/sm/Elements/lattice3dboundary.h	20% <20%> (ø)
src/sm/Elements/lattice3d.h	22.22% <22.22%> (ø)
src/sm/Materials/latticematstatus.h	33.33% <30%> (+33.33%)	⬆️
src/sm/Materials/latticelinearelastic.C	33.93% <33.93%> (ø)
src/sm/Materials/structuralmaterial.C	60.07% <43.13%> (+0.18%)	⬆️
... and 22 more

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