Polishing icons, forgetting nodes, matrix nodes to matrix category

Слиты nikitronn запросил слияние github/fork/vicdoval/better_icons_b28 в b28_prelease_master

Created by: vicdoval

A lot for a PR but I hope you don't mind in this case. The PR covers this topics _Polishing some icons and adding some more to the new nodes. image

_Take action on #2601 (closed) _Matrix category filled with Beta Matrix Nodes image image

_Added Matrix Normal Docs

  • Ready for merge.