[MLIR] Break cyclic dependencies with MLIRAnalysis

Summary:

MLIRAnalysis depended on MLIRVectorOps
MLIRVectorOps depended on MLIRAnalysis for Loop information.

Both of these can be solved by factoring out libraries related to loop
analysis into their own library. The new MLIRLoopAnalysis might be
better off with the Loop Dialect in the future.

Reviewers: nicolasvasilache, rriddle!, mehdi_amini

Reviewed By: mehdi_amini

Subscribers: Joonsoo, vchuravy, merge_guards_bot, mgorny, mehdi_amini, rriddle, jpienaar, burmako, shauheen, antiagainst, arpith-jacob, mgester, lucyrfox, aartbik, liufengdb, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73655