Support snapshot-rw isolation mode in ydb cli

[zverevgeny]

API:

ydb/ydb/public/api/protos/ydb_query.proto

Line 67 in 8ed59d5

message SnapshotRWModeSettings {

ydb/ydb/public/api/protos/ydb_table.proto

Line 1060 in 8ed59d5

message SnapshotRWModeSettings {

C++ SDK already supports this mode

Need to support --tx-mode option (with all supported tx modes, includes snapshot isolation mode) in ydb sql command (like ydb table query execute):

ydb table query execute --help
Usage: ydb [global options...] table query execute [options...]

Description: Execute query

Global options:
  {-e|--endpoint}, {-d|--database}, {-v|--verbose}, {-p|--profile}, {-y|--assume-yes}, --ca-file, --client-cert-file, --client-cert-key-file, --client-cert-key-password-file, --iam-token-file, --yc-token-file, --use-metadata-credentials, --sa-key-file, --token-file, --user, --password-file, --no-password, --oauth2-key-file, --iam-endpoint, --profile-file
  To get full description of these options run 'ydb --help'.

Options:
  {-h|--help}            Print usage, -hh for detailed help
  --timeout ms           Operation timeout. Operation should be executed on server within this timeout. There could also be a delay up to 200ms to receive timeout error from server.
  --help-ex              Print usage with examples
  {-t|--type} [String]   Query type [data, scheme, scan, generic] (default: data)
  --stats [String]       Collect statistics mode (for data & scan & generic queries) [none, basic, full]
  --flame-graph PATH     Builds resource usage flame graph, based on statistics info
  -s                     Collect statistics in basic mode
  --tx-mode [String]     Transaction mode (for generic & data queries) [serializable-rw, online-ro, stale-ro, notx (generic queries only)] (default: serializable-rw)
...