Re-organize documentation of beta and alpha DRA subfeatures

[reylejano]

Follow-up to https://github.com/kubernetes/website/pull/54541/changes#r2980143738
Re-organize documentation of alpha and beta DRA subfeatures to where they belong if they were stable

[lmktfy]

/triage accepted

[yashrajshuklaaa]

i'd like to work on this issue

[yashrajshuklaaa]

/assign