Get codicons from node module (#289705)

* Revert "Revert codicon change (#289683)"

This reverts commit de6f371a92ad8bd85ff0e70ac737ea21b5d0230e.

* Always run postinstall

* Two more places

* Move codicon copy into compilation

* Fix pipelines

* Update readme

* Fix watch task

* Move copy codicons

* MIssed some spots

* Error handing

* Fix path