feat: Add bucket schema management commands (#52)

* feat: update generated client to include schema-management APIs
* feat: implement interfaces to decode flags and CSV
* feat: implement decoders for different measurement schema column formats
* feat: extend bucket CLI commands to support schema type property
* feat: add CLI commands to manage measurement schema
* test: add unit tests for bucket schema create, update and list commands

internal/cmd/bucket_schema/format.go

@@ -0,0 +1,86 @@
+package bucket_schema
+
+import (
+	"fmt"
+	"io"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"github.com/influxdata/influx-cli/v2/internal/api"
+)
+
+// ColumnsFormat is a type which defines the supported formats
+//
+type ColumnsFormat int
+
+const (
+	ColumnsFormatAuto ColumnsFormat = iota
+	ColumnsFormatCSV
+	ColumnsFormatNDJson
+	ColumnsFormatJson
+)
+
+func (f *ColumnsFormat) Set(v string) error {
+	switch v {
+	case "auto":
+		*f = ColumnsFormatAuto
+	case "csv":
+		*f = ColumnsFormatCSV
+	case "ndjson":
+		*f = ColumnsFormatNDJson
+	case "json":
+		*f = ColumnsFormatJson
+	default:
+		return fmt.Errorf("invalid columns-format: %s, expected [csv, ndjson, json, auto]", v)
+	}
+	return nil
+}
+
+func (f ColumnsFormat) String() string {
+	switch f {
+	case ColumnsFormatAuto:
+		return "auto"
+	case ColumnsFormatCSV:
+		return "csv"
+	case ColumnsFormatNDJson:
+		return "ndjson"
+	case ColumnsFormatJson:
+		return "json"
+	default:
+		return "schema.Format(" + strconv.FormatInt(int64(f), 10) + ")"
+	}
+}
+
+// DecoderFn uses f and path to return a function capable of decoding
+// measurement schema columns from a given io.Reader. If no combination
+// of decoder exists for f and path, DecoderFn returns an error.
+func (f ColumnsFormat) DecoderFn(path string) (ColumnsDecoderFn, error) {
+	ff := f
+	if ff == ColumnsFormatAuto {
+		ext := filepath.Ext(path)
+		switch {
+		case strings.EqualFold(ext, ".csv"):
+			ff = ColumnsFormatCSV
+		case strings.EqualFold(ext, ".json"):
+			ff = ColumnsFormatJson
+		case strings.EqualFold(ext, ".ndjson") || strings.EqualFold(ext, ".jsonl"):
+			ff = ColumnsFormatNDJson
+		}
+	}
+
+	switch ff {
+	case ColumnsFormatCSV:
+		return decodeCSV, nil
+	case ColumnsFormatNDJson:
+		return decodeNDJson, nil
+	case ColumnsFormatJson:
+		return decodeJson, nil
+	}
+
+	return nil, fmt.Errorf("unable to guess format for file %q", path)
+}
+
+// ColumnsDecoderFn is a function which decodes a slice of api.MeasurementSchemaColumn
+// elements from r.
+type ColumnsDecoderFn func(r io.Reader) ([]api.MeasurementSchemaColumn, error)