Integrate ReRAM documentation

[proppy]

Expected Behavior

ReRAM documentation is available on https://skywater-pdk.readthedocs.io/

Actual Behavior

ReRAM documentation is only available at https://sky130_fd_pr_reram.rtfd.io/.

Steps to Reproduce the Problem

1. Open https://skywater-pdk.readthedocs.io/en/main/search.html?q=ReRAM

[sebastien-riou]

now https://sky130_fd_pr_reram.rtfd.io/ is dead, so the ReRAM seems to not be available at all.

[RTimothyEdwards]

@sebastien-riou : What do you mean by "dead"? It's there. It doesn't get updated much. If you want to understand ReRAM, be part of the group discussions on the open-source-silicon slack workspace.

[sebastien-riou]

@RTimothyEdwards I meant that I get an error message "Bad request (400)". I figured it out only now that it works with this link: https://sky130-fd-pr-reram.readthedocs.io/en/latest/index.html