fix(libcurl_http_fetcher): Move curl specific GetProxyType

This function appears to be the only reason why chrome_proxy_resolver
exists at all but it is just a utility function for libcurl. Move it to
its rightful home so the other code can be removed.
remove(chrome_proxy_resolver): Unused in current code base.

This code was replaced a long long time ago by 000d895d but no one
bothered to actually delete it.
remove(chrome): Remove support for querying Chrome for proxies.

We have no use for this, later we need to implement support for using
proxy information from environment variables instead.
remove(metrics): Remove calls to metrics library.

We do not use the ChromeOS metrics daemon to gather system information.
The limited info we do gather is just reported to the update service.
Note: this does not remove the code that generates the info being
submitted, just the calls themselves, the rest will go in a follow up.
remove(metrics): Remove most metrics support code.

Remove code for reporting metrics to UMA, we only report to Omaha.
chore(dbus_service): Remove now unused dbus methods.

These methods have been unused since f6035bf7.
Merge pull request #33 from marineam/cleanup

Delete over 1k lines and one whole library