Add missing.js test files that requires any files that currently does
not have any unit tests defined for them. This should hopefully make it
so that when unit tests are added for parts of these files the coverage
will increase instead of decreasing.
Note that this does not include CLI Tools/ as those are not testable.
Replace the instancedirectory variable with an Instance class that holds
the directory and has a .path() to get paths relative to the instance
directory.
Rewrite the generateSSLcert lib to be async, use the sslCert and
sslPrivKey config entries and invoke it only if needed during master
server startup instead of in the post install script. Also add note to
the changelog covering both this and the fix in c645fac.