chore: hoist configuration to top level

[d-jeffery]

Hoisted configuration files to extension top level for organization. Files do not need to be under client to be packaged or referenced.

Description

Moved up to top level for consistency with other LSP extensions;

• syntax
• themes
• language-configuration.json

Also added LICENSE file

openfga-vscode-1.0.0.vsix.zip

References

Following are examples from vscode extension samples package

• Snippets: https://github.com/microsoft/vscode-extension-samples/tree/main/snippet-sample
• Theme: https://github.com/microsoft/vscode-extension-samples/tree/main/theme-sample
• Language config: https://github.com/microsoft/vscode-extension-samples/tree/main/language-configuration-sample
• Syntax: https://github.com/microsoft/vscode-extension-samples/tree/main/lsp-embedded-language-service

VSCode clients with language config / syntax / snippets at top level of package.

• RestClient: https://github.com/Huachao/vscode-restclient
• DB Client: https://github.com/cweijan/vscode-database-client
• as2: https://github.com/admvx/as2-language-support

Counter example:

• https://github.com/Beaglefoot/awk-language-server

Review Checklist

• I have clicked on "allow edits by maintainers".
• I have added documentation for new/changed functionality in this PR or in a PR to openfga.dev [Provide a link to any relevant PRs in the references section above]
• The correct base branch is being used, if not main
• I have added tests to validate that the change in functionality is working as expected

[rhamzeh]

consistency with other LSP extensions

Can you provide a link to those extensions or documentation about this?