[mlir][Analysis] Add batched version of FlatAffineConstraints::addId

* Add batched version of all `addId` variants, so that multiple IDs can be added at a time.
* Rename `addId` and variants to `insertId` and `appendId`. Most external users call `appendId`. Splitting `addId` into two functions also makes it possible to provide batched version for both. (Otherwise, the overloads are ambigious when calling `addId`.)

Differential Revision: https://reviews.llvm.org/D108532