[#7] Add local tool for building database file

Added frostfs-locode-db CLI utility that can generate and view UN/LOCODE
database files. Go package
git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/locode copied to
this repository to eliminate interdependency between frostfs-node and
frostfs-locode-db projects. The process of building database files
reduced to starting make command.

Signed-off-by: George Bartolomey <george@bh4.ru>

pkg/locode/db/location.go

@@ -0,0 +1,32 @@
+package locodedb
+
+import (
+	"fmt"
+
+	locodecolumn "git.frostfs.info/TrueCloudLab/frostfs-locode-db/pkg/locode/column"
+)
+
+// LocationCode represents a location code for
+// the storage in the FrostFS location database.
+type LocationCode locodecolumn.LocationCode
+
+// LocationCodeFromString parses a string UN/LOCODE location code
+// and returns a LocationCode.
+func LocationCodeFromString(s string) (*LocationCode, error) {
+	lc, err := locodecolumn.LocationCodeFromString(s)
+	if err != nil {
+		return nil, fmt.Errorf("could not parse location code: %w", err)
+	}
+
+	return LocationFromColumn(lc)
+}
+
+// LocationFromColumn converts a UN/LOCODE country code to a LocationCode.
+func LocationFromColumn(cc *locodecolumn.LocationCode) (*LocationCode, error) {
+	return (*LocationCode)(cc), nil
+}
+
+func (l *LocationCode) String() string {
+	syms := (*locodecolumn.LocationCode)(l).Symbols()
+	return string(syms[:])
+}