Add settings retrieval through properties file and env vars - #1176

At the the Java coding point of view, it may be useful for developers can read the properties file from some options like follows.

1. Read properties from under the class pass, For example
   src/main/java/resources/openaiconf.properties
   String resourcePath = Thread.currentThread().getContextClassLoader().getResource("").getPath();

2. Environment variable
   It seems that .NET is also using the environment variable
   https://github.com/microsoft/semantic-kernel/tree/main/samples/dotnet/kernel-syntax-examples

3. Finally, like this implementation, user can specify the directory and file name out side of the class path.
   (This coding)

The second point is already supported using Settings.getOpenAISettingsFromEnv and Settings.getAzureOpenAISettingsFromEnv.

Added some changes to support multiple client configuration (description updated).

Milder Hernandez (@milderhc) Can you rebase and see if we can land this PR?

Dear Milder Hernandez (@milderhc) san

Thank you so much for your hard work. I much appreciate.

BTW, from the Developers Point of view,
As you know, especially Spring user may want to use with following value (@value) annotation.
So please confirm, your new implementation is available with the above annotation too.

For Example:

https://github.com/yoshioterada/MS-OpenAI-Java-Lib-Sample/blob/048df7556ef5517aa81551dcdd09179348706be0/src/main/java/com/yoshio3/SSEOpenAIController.java#L40-L50

https://github.com/yoshioterada/MS-OpenAI-Java-Lib-Sample/blob/048df7556ef5517aa81551dcdd09179348706be0/src/main/resources/application.properties#L1-L4

Thanks! I like that option, but I would prefer it for a specific Spring settings implementation, if something like that is added later.