Change source/manuscript IDs to match the IDs in Cantus Database

related to [Issue 429](https://github.com/DDMAL/CantusDB/issues/429#issuecomment-1327839305) on the CantusDB github page, I figured it would be a good idea to open the issue here, where the impactful change would actually occur.

Since Cantus Ultimus is more-or-less a nice user interface over top of the data on CantusDB, it might make sense to **change the manuscript identifier numbers in Cantus Ultimus to match those in CantusDB** - for example, CH-E 611 is currently [74 in CU](https://cantus.simssa.ca/manuscript/74/), but [123606 in CD](https://cantus.uwaterloo.ca/source/123606). This would make it easy to link to a manuscript from CantusDB, and it also feels like a thing that would generally make integration between the two sites simpler in other situations.

(I have not looked through all of the issues that are open on this repository, so if this is a duplicate, feel free to close it)