[Due 20 March] Update platform support page for Qiskit 2.0

[mtreinish]

As we approach Qiskit 2.0 we'll need to update the platform support section in https://docs.quantum.ibm.com/guides/install-qiskit#operating-system-support to reflect changes made to the platform support in 2.0. Right now the only change is the removal of 32bit platform support from tier 3 (see Qiskit/qiskit#13650).

Since there is a divergence in the two different release series we might need to split this out into a 2.x and 1.x subsection. Since 1.x will support more platforms than 2.x. I'm opening this issue to make sure we don't forget to do this, but we don't have anything to do here until we get closer to the 2.0.0 release.