Revert "[RVec] Simplify and document implementation"
Revert "[RVec] Simplify and document implementation"

This reverts commit 4149e4fa375d549cf00e3b9cc4265e7b42b0f090.

Reverting RVec's SBO implementation until we have a proper fix
for the crashes seen in ROOT-10079.

karies/root,olifre/root,karies/root,olifre/root,root-mirror/root,karies/root,root-mirror/root,olifre/root,olifre/root,karies/root,olifre/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,karies/root,root-mirror/root,karies/root,karies/root,olifre/root,karies/root,root-mirror/root,root-mirror/root,karies/root,karies/root,olifre/root,root-mirror/root,olifre/root,root-mirror/root,root-mirror/root,karies/root,olifre/root,root-mirror/root