Use default data converter for search attributes and memo

[vitarb]

What was changed:

Custom data converters used with search attributes and memo result in failures down the line when we try to put data into ES.

Why?

Proposal that may address #468

[GreyTeardrop]

I wonder if there can still be a reason to use a custom data converter for search attributes? E.g. if Kotlin data class is used as attribute value then KotlinModule should be registered with the ObjectMapper used by the converter.

[Spikhalskiy]

Just to echo @GreyTeardrop comment. If search attributes can be any object (judging from the fact it's Map<String, Object>) - we need to have custom converters. Otherwise, the default converter will not be able to deal with Kotlin objects for example.

I see that Maxim commented the following in #468: "But the format of the search attribute serialization is fixed by the service."
Are we strictly limited by what can be a search attribute and these classes are provided by Temporal + Java SDK and all of them are final?

-----UPDATE------
Answering my own question (from here https://docs.temporal.io/docs/server/workflow-search/):

Search attributes must be one of the following types:
string
keyword
int
double
bool
datetime

So we should be good with using the default converter. But a nice long comment that is explaining this would be really useful in the code about why do we treat search attributes differently.

[vitarb]

So it looks like we are in agreement that we should make this change, let me brush it up a bit then.