[Proposal] Support a LitmusChaos Java SDK (#4871)

* add litmus java sdk proposal

Signed-off-by: Jemin <jemin9812@gmail.com>

* update java-sdk-proposal

Signed-off-by: Jemin <jemin9812@gmail.com>

* docs: add usecase of sdk

Signed-off-by: Jemin <jemin9812@gmail.com>

---------

Signed-off-by: Jemin <jemin9812@gmail.com>
Co-authored-by: Namkyu Park <53862866+namkyu1999@users.noreply.github.com>

Author: jemlog

proposals/java-sdk.md

@@ -0,0 +1,94 @@
+| title               | authors                              | creation-date | last-updated |
+|---------------------|--------------------------------------|---------------|--------------|
+| add litmus java sdk | [@jemlog](https://github.com/jemlog) | 2024-09-07    | 2024-09-07   |
+
+# Adding Litmus Java SDK
+
+- [Adding Litmus Java SDK](#adding-litmus-java-sdk)
+  - [Summary](#summary)
+  - [Motivation](#motivation)
+    - [Goals](#goals)
+    - [Non-Goals](#non-goals)
+  - [Proposal](#proposal)
+    - [Use Cases](#use-cases)
+    - [Implementation Details](#implementation-details)
+      - [Initialize client](#initialize-client)
+      - [Use Client](#use-client)
+  - [Risks and Mitigations](#risks-and-mitigations)
+  - [Upgrade / Downgrade Strategy](#upgrade--downgrade-strategy)
+  - [Drawbacks](#drawbacks)
+  - [Alternatives](#alternatives)
+  - [References](#references)
+
+## Summary
+
+The purpose of litmus-java-sdk is to provide a client that can easily access to auth and backend server of litmus.
+
+## Motivation
+
+Litmuschaos’ backend server uses graphQL as an API communication method. 
+Graphql is not as familiar to developers as REST API, so it is difficult to call backend server directly. 
+Therefore we planned to add a Java-based SDK that makes developers to communicate easily with litmus backend server. 
+The SDK also provides an interface to communicate with the auth server to wrap the entire litmus control plane.
+
+### Goals
+
+- Add client calling the API for Auth Server
+- Add client calling graphQL for Backend Server
+
+
+### Non-Goals
+
+- Changing APIs that auth server and backend server already provide is non-goal
+- Add auto configuration for SpringBoot is non-goal
+
+## Proposal
+
+### Use Cases
+
+In organization, litmusChaos administrators can call java SDK to manage multiple users and projects.
+
+### Implementation Details
+
+#### Initialize client
+
+```java
+public void init(){
+
+  String hostUrl = "http://localhost:3000";
+  String username = "admin";
+  String password = "litmus";
+
+  LitmusClient litmusClient = new LitmusClient(hostUrl, username, password);
+}
+```
+#### Use Client
+```java
+public void execute(){
+
+    String projectName = "demo project";
+    String description = "demo project description";
+    List<String> tags = Arrays.asList("litmus", "chaos");
+
+    CreateProjectRequest request = CreateProjectRequest.builder()
+        .projectName("project")
+        .description("description")
+        .tags(tags)
+        .build();
+
+    CreateProjectResponse response = litmusClient.createProject(request);
+}
+```
+## Risks and Mitigations
+
+## Upgrade / Downgrade Strategy
+
+## Drawbacks
+
+It will be a great opportunity for administrators of litmusChaos to manage users and conduct experiments more conveniently.
+
+## Alternatives
+
+This is the first java sdk we created in Litmus. No other alternatives exist.
+
+## References