Feat(dynamic): Dynamic content pages have been added (rather than
hardcoded HTML. This is Skipper dog fooding itself (I.E. Skipper
now makes requests to itself to pull content for these dynamic pages).
This commit also adds initial support for an "official" Skipper Go API.
This is nice as the API satisfies interfaces Skipper itself uses
internally (E.G. m/content, m/value).
Feat(pkg/flushresp): Break out wrapped response writer into its own
Feat(pkg/e3): Complete testing for E3 client code.
Chore(e3/defaultDepth/redirect): Slight changes. Moving things around.
Feat(go.mod): Dependency cleanup. Removed some.
Feat(private files): Upload files to E3 as private.
Feat(e3): Making E3 integration better. Adding tests. Potentially use as
future ref to pointer users toward to help them implement E3.