Add no-concatenation and max-concatenation modes to rivet-build, tested in CI

This patch adds modes to rivet-build that either put one analysis per concatenated "bucket", or all the analyses in that plugin into a single bucket. Each bucket is a single compilation unit. The modes are for internal purposes only, so they are controlled by env variables rather than new command-line switches. The CI config is updated to use the no-cat mode in individual analysis tests, and the max-cat mode in the monthly full validation. Broken analyses have been fixed at the same time.