Support reordering operations for Grid

[termi-official]

We should add renumber!(grid, order). This can be useful if we want to add data locality optimization strategies in the future.

[Jay-sanjay]

Hi @termi-official I would like to work on this issue, can you please tell me what kind of function renumber!( ) must be .
I see there is some things related to it here

Ferrite.jl/src/Dofs/DofRenumbering.jl

Line 62 in fe44e7f

renumber!

but I am not clear what needs to be done

[termi-official]

The idea is similar to the dof renumbering. Basically the grid has an array of cells and nodes

Ferrite.jl/src/Grid/grid.jl

Lines 316 to 317 in fe44e7f

	cells::Vector{C}
	nodes::Vector{Node{dim,T}}

where the cells hold indices to the node array. So the function basically has to change the node locations on the nodes array of the grid and the indices in the cells respectively.