As the queries live here, it makes sense for the suites to be versioned
together with them. The LGTM suite has already been moved. This commit
moves the actively-maintained non-LGTM suites.
This follows what's been done for JavaScript. The `cpp-alerts-lgtm`
suite is now empty and will be auto-generated when building a dist.
This commit has no effect in itself, but these files need to be in place
when the corresponding changes are made in Semmle/code.