LPS-51413 As a system administrator I'd like to use 2-way SSL authentication against my SOLR server

Hi André,

It's me again. I found the following modifications useful.

1) https://github.com/laszlocsontos/liferay-plugins/commit/020d034482443c07f5601e0d6c41a19ee0f6badd
It looks like all implementers of this interface will use these three setter methods. I think it will be easier for future modifications to add methods first here then to descendant classes.

2) https://github.com/laszlocsontos/liferay-plugins/commit/f4c6df7e6b1ab0a0eed1bf6ae5517bfe479f5b38
I draw a class diagram for myself and after finishing is BasePoolingHttpClientFactory seems to be an odd-one-out in terms of not implementing HttpClientFactory. I think it meant to implement, right?

3) https://github.com/laszlocsontos/liferay-plugins/commit/c6ccbc02e6df8568139124ba07bfe5d0ee49f05f
As KeyStoreLoader doesn't maintain an internal state, I think it could be static class instead.

4) https://github.com/laszlocsontos/liferay-plugins/commit/4a696fd21e03709971a95412d56761a8fbc8d86d
This was a bug in my original implementation, that is, if we bypass server's certificate validation, we don't have to load the trust store.

5) https://github.com/laszlocsontos/liferay-plugins/commit/7d4c4ff01806d5b9c2671fa3295ab037f25aefde
Minor SF

6) https://github.com/laszlocsontos/liferay-plugins/commit/6653bd272e21137f86690623440327e1ba362c73
Was that any special reason you used primitive ints here?

I haven't tested anything yet, just tried to understand the new structure. If you found my modifications right, could you please squashing them and send a PR back to me?

Thanks,
László

/cc: @mhan810