Implement `toString()` method in `MongoTableHandle` and `RemoteTableName` classes

[ebyhr]

Description

Implement toString in MongoTableHandle and RemoteTableName to improve EXPLAIN readability.

Before:

trino> EXPLAIN SELECT * FROM  mongodb.tpch.region WHERE name = 'X';
                                                                                                                                                                                  Query Plan
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Trino version: testversion
 Fragment 0 [SOURCE]
     Output layout: [regionkey, name, comment]
     Output partitioning: SINGLE []
     Output[columnNames = [regionkey, name, comment]]
     │   Layout: [regionkey:bigint, name:varchar(25), comment:varchar(152)]
     │   Estimates: {rows: ? (?), cpu: 0, memory: 0B, network: 0B}
     └─ TableScan[table = mongodb:MongoTableHandle[schemaTableName=tpch.region, remoteTableName=RemoteTableName[databaseName=tpch, collectionName=region], filter=Optional.empty, constraint={name:varchar(25)=[ SortedRangeSet[type=varchar(25), ranges=1, {[X]}] ]}, projectedColumns=[regionkey:bigint, name:varchar(25), comment:varchar(152)], limit=OptionalInt.empty]]
            Layout: [regionkey:bigint, name:varchar(25), comment:varchar(152)]
            Estimates: {rows: ? (?), cpu: ?, memory: 0B, network: 0B}
            comment := comment:varchar(152)
            regionkey := regionkey:bigint
            name := name:varchar(25)

After:

trino> EXPLAIN SELECT * FROM  mongodb.tpch.region WHERE name = 'X';
                                                              Query Plan
---------------------------------------------------------------------------------------------------------------------------------------
 Trino version: testversion
 Fragment 0 [SOURCE]
     Output layout: [regionkey, name, comment]
     Output partitioning: SINGLE []
     Output[columnNames = [regionkey, name, comment]]
     │   Layout: [regionkey:bigint, name:varchar(25), comment:varchar(152)]
     │   Estimates: {rows: ? (?), cpu: 0, memory: 0B, network: 0B}
     └─ TableScan[table = mongodb:tpch.region constraint on [name] columns=[regionkey:bigint, name:varchar(25), comment:varchar(152)]]
            Layout: [regionkey:bigint, name:varchar(25), comment:varchar(152)]
            Estimates: {rows: ? (?), cpu: ?, memory: 0B, network: 0B}
            comment := comment:varchar(152)
            name := name:varchar(25)
            regionkey := regionkey:bigint

Release notes

(x) This is not user-visible or is docs only, and no release notes are required.