feat: Add user management resources and data sources

[gpontejos]

Adding the following:

• crowdstrike_user resource: Creates a single crowdstrike user in the Falcon console.
• crowdstrike_user_role_assignment resource: Adds roles to an existing user.
• crowdstride_user data source: Get information from an existing user.
• crowdstrike_user_roles data source: Retrieves all roles so that you can filter and dynamically add roles to user.