internal/testing/fakedatasource: improve doc

go.mod: update golang.org/x dependencies

internal/frontend: add v1/search endpoint

internal/api: refactor error handling to increase consistency

internal/api: test licenses and imports params

internal/api: simplify filter code

internal/api: set cache-control headers

internal/api: add examples parameter to PackageParams

internal/queue: add postgres queue implementation, and use it in worker|frontend

internal/frontend: remove local map of case sensitive excluded paths

internal/postgres: allow matching exact prefix with exact:

internal/api: clean up redundant TODO

internal/api: add support for readme and licenses in ServeModule

internal/api: unify default pagination limits

internal/api: refactor ServePackage and extract helper functions