~gbmor/getwtxt

ref: c37aa835d01010af1c486dec6625717a50472fc8 getwtxt/registry d---------
fixed test case for fetching remote registry data
conditionally parsing datestamp as either rfc3339Nano or rfc3339
updating module to live at sourcehut

Also moving the 'registry' library into this repo, rather
than maintaining them separately. It will still be decoupled,
just live in this repository.
moved registry library to separate repo
initialized new go module for registry library
fleshing out Indexer interface
exported Data struct fields
moved query functions to own file, made SortByTime query-agnostic
package cache renamed to package registry