Update the builtin metrics support

[jmacd]

Is your feature request related to a problem? Please describe.
The builtin metrics provided by this library are out-of-date with respect to the OTel specifications and with respect to the Go-teams runtime/metrics package. A complete update to this problem includes:

1. An option to disable runtime metrics: Add an option to disable builtin metrics LS-33360 #265
2. Update for go-contrib's instrumentation/runtime package to expose go-team's standard runtime/metrics: New runtime/metrics instrumentation #267
3. Update for go-contrib's instrumentation/host to stop it from exposing process cpu timing: Lightstep fork of go-contrib instrumentation/host metrics #268
4. New instrumentation package to expose process cpu timing, including proposed candidates for new Go runtime/metrics: CPU runtime and timing metrics #269.

Describe the solution you'd like
See the links above for individual changes.
To combine these into a new otel-launcher-go release, one additional option will be needed. I suggest the following:

LS_METRICS_BUILTINS_NAMED=one,two,three

where one, two, and three are short-names of known builtin instrumentation. We will not change any defaults in the 1.x otel-launcher-go release series, instead we will provide configuration options to choose the new experimental instrumentation, for now. When otel-launcher-go 2.x is released, it can update to the new, preferred libraries by default. By then, we should be able to merge our new instrumentation with the upstream repository, probably in the form of new packages.