DataTypeConverter usage has potential thread-safety issues

## Description

_This is not an explicit bug report in the sense that I haven't experienced a problem (yet?), it is just something I bumped into while browsing the code_.

`DataTypeConverter` has a [javadoc comment stating that it is not thread safe](https://github.com/ClickHouse/clickhouse-java/blob/main/client-v2/src/main/java/com/clickhouse/client/api/internal/DataTypeConverter.java#L25). For what it's worth, I have also confirmed thread safety problems because I ended up using the `DataTypeConverter.INSTANCE` in production (before I realised that it was labelled as non thread safe) which caused some bugs.

After fixing the bugs in my project, I was curious about the fact that a static singleton `DataTypeConverter.INSTANCE` was even declared in the `clickhouse-java` repo (why have a singleton instance if it is not thread safe, in an otherwise thread safe library?). Of course this class is in a package named `internal`, so it's not really my business... :) Still, I did notice that `DataTypeConverter.INSTANCE` is used in [two](https://github.com/ClickHouse/clickhouse-java/blob/8da0b0c9aa7995b9fa839b56861a28047f71076a/client-v2/src/main/java/com/clickhouse/client/api/data_formats/internal/MapBackedRecord.java#L48) [places](https://github.com/ClickHouse/clickhouse-java/blob/8da0b0c9aa7995b9fa839b56861a28047f71076a/client-v2/src/main/java/com/clickhouse/client/api/data_formats/internal/AbstractBinaryFormatReader.java#L90) which makes me wonder if it could be the source of (other / future / not-yet-encountered) problems..