Added ssl&proxy properties to RestSdmxClient.

[charphi]

These properties are used to programmatically customize how a client access a web service.

[amattioc]

Hi @charphi , thanks for the PR.

Could you explain briefly what would be the benefits of having these properties at the client level?

Best, Attilio

[charphi]

Sure. Here is the use case:
The current system defines ssl&proxy at the application level. It means that if you configure Internet access with it, every component of the application will have that access.
I need to restrict Internet access to the SDMX client only.

[amattioc]

Thanks for the explanation.

[charphi]

@amattioc @vpinna80 The content of this pull request is not more available in the latest commit 5ff9020. So, I'm no more able to modify ssl&proxy by code.

[vpinna80]

@charphi This should be fixed now with 8ea3ccd.

[charphi]

Indeed, I've just tested and it works properly. Thanks.