STX-211 Implement contexts support and a few minor changes (1)

[valkovich-ds]

📋 Type of the Changes

• Breaking change
• Non-breaking change
• Bug fix / minor change

🛠 Changes being made

NOTE: Native image build temporary disabled. I'd propose to fix it after Kamil's build improvements will be merged, as well as other PRs from this series.

• ⚠️⚠️⚠️ Before merge ⚠️⚠️⚠️ - decide what we set for these application properties:

streamx.defaults.auth.server-url=...
streamx.defaults.platform.url=...

Currently it point to a temporary dev server. It should point to default streamx.com prod URLs.

Contexts feature

CLI user can have multiple StreamX contexts on a single machine and switch between them.

All the settings, event templates, login credentials, etc., are stored per context.

Stored in ~/.streamx/contexts/<context_name>/.

The default context file structure is created on first use.

The current context is stored in ~/.streamx/current-context

Selection precedence: -C/--context flag > STREAMX_CONTEXT env > current-context pointer file > default.

For context management, these commands are implemented: streamx context create|list|use|current|delete

Other changes

• Introduced reusable TextTable renderer is used for all list commands to guarantee consistent formatting.
• Introduced DeleteConfirmation renderer for destructive operations.
• Improved zsh autocompletion generation to support contexts.

✅ Checklist

• My code follows the code standards of this project
• Changed code is covered with unit tests
• I have updated READMEs and java docs (if applicable)