make colums in software overview page less wide

[boegel]

To avoid the very broad columns in the software overview page, can we add shorthands + a legend above the table?

For example:

• hsw for haswell
• skl for skylake_avx512
• spr for sapphirerapids
• nv_n1 for neoverse_n1
• nv_v1 for neoverse_v1

[laraPPr]

Another thing to make the table more attractive is to use emojis instead of the x marks