Dev environment fixes and cleanup

[RoeiDimi]

1. create a folder envsInstallationResources to hold a folder per Logstash version. each such folder holds all the needed resources to build a container with a running Logstash in that version
2. move current installation resources for Logstash 8.16 from src folder to envsInstallationResources folder
3. add devcontainer.json change to make Logstash run once the dev container is up - this will allow immediately clicking "debug" and the debugger should connect to the running Logstash instance
4. add devcontainer.json change to install the Extension Pack for Java in Visual Studio
5. change plugin name due to this constraint - https://github.com/elastic/logstash/blob/e094054c0e99382aa3e2c666cbd2f1046c1e1da2/rubyUtils.gradle#L419
6. update Readme.md to explain about debugging

[Copilot]

Copilot reviewed 9 out of 9 changed files in this pull request and generated no comments.

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src/main/java/org/logstashplugins/MicrosoftSentinelOutput.java:18

• Verify that renaming the plugin to 'microsoft_sentinel_output' adheres to the required Logstash plugin naming conventions. If this is intentional, confirm that all dependent configurations and documentation are updated accordingly.

@LogstashPlugin(name = "microsoft_sentinel_output")

README.md:40

• Ensure that the updated plugin name 'microsoft_sentinel_output' is used consistently across all documentation examples in the README. Double-check that any remaining references to the old plugin name are updated if needed.

microsoft_sentinel_output {