Add mps 1.113.0, fix usage of Sleepycat license

MPS is the "Memory Pool System", a Garbage collection and memory management library from Ravenbrook.

MPS is traditionally used 'inline' without an autoconf-packaged distribution, but this package also installs its telemetry tools and debugging libraries, which are quite useful in practice for client applications.

MPS is under the Sleepycat license (and dually a commercial license). So I took the time to add it to `licenses.nix` and fixed up the uses of it. `ike` and `db` were the only other packages I could find, which I fixed to use sleepycat instead.