Move compiler loading out of libsinsp/lua_parser.cpp and into a new
class in digwatch/rules.cpp.
This way the libsinsp support is strictly about providing a lua API for
scripts to setup filters. Loading the actual parser and rules is logic
that belongs in the app (digwatch in this case, maybe sysdig down the
line) rather than there.
This commit removes the one remaining (known) difference with the sysdig
c++ parser: relational expression right-hand sides now _only_ need to be
quoted if they contain a paren or a space.
So you can now do things like "fd.name contains (.log and event.dir = <"
without needing to quote "*.log" or "<".
