This pull request adds support for managing and using text snippets in the bot, including database migration, command registration, and integration with existing reply and anonreply commands. Users can now store reusable snippets and reference them in replies using a special syntax or command options.

Database and Migration:

• Added a new snippets table to the database with fields for key, content, creator, and timestamps, along with an index for efficient lookup.
• Introduced SQL query definitions for creating, retrieving, updating, and deleting snippets.

Command Registration and Structure:

• Registered the new SnippetCommand and included module imports for snippet-related commands in the bot command registry.
• Added module structure for snippet commands, supporting both slash and text command styles.

Reply and Anonreply Command Integration:

• Updated both reply and anonreply text commands to support referencing a snippet by using {{snippet_key}} syntax; the content is replaced with the snippet if found, otherwise an error is returned.
• Enhanced the reply slash command to accept an optional snippet argument, fetch its content from the database, and use it in the reply.