[analyzer] ApiModeling: Add buffer size arg constraint

Summary:
Introducing a new argument constraint to confine buffer sizes. It is typical in
C APIs that a parameter represents a buffer and another param holds the size of
the buffer (or the size of the data we want to handle from the buffer).

Reviewers: NoQ, Szelethus, Charusso, steakhal

Subscribers: whisperity, xazax.hun, baloghadamsoftware, szepet, rnkovacs, a.sidorin, mikhail.ramalho, donat.nagy, dkrupp, gamesh411, ASDenysPetrov, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D77066