Rename base package to git.monogon.dev/source/smalltown.git

This ensures that the package is go get-able in our managed environment,
which has SSH configs for git.monogon.dev by default.

go knows that it's a Git repo by matching on ".git"
(see: https://golang.org/cmd/go/#hdr-Remote_import_paths).

The package name is a bit more unwieldy than it needs to be, so maybe
we should add go-import metadata to git.monogon.dev at some point
(which is not straight-forward, since Go does not understand SRV records,
so this needs to be added to the Phabricator web server).

Also refreshed all generated files and go.mod/go.sum.

Test Plan:
    make cmd/mkimage/mkimage
    make cmd/init/init

X-Origin-Diff: phab/D193
GitOrigin-RevId: 766325ccd9a51d04eba0e49269c530c520444193
diff --git a/internal/storage/find.go b/internal/storage/find.go
index 72d3f6a..3a708c2 100644
--- a/internal/storage/find.go
+++ b/internal/storage/find.go
@@ -18,10 +18,10 @@
 
 import (
 	"fmt"
+	"git.monogon.dev/source/smalltown.git/pkg/sysfs"
 	"io/ioutil"
 	"os"
 	"path/filepath"
-	"smalltown/pkg/sysfs"
 	"strconv"
 
 	"github.com/rekby/gpt"