Add changie to facilitate release notes

[mattdot]

This pull request introduces a new changelog system using Changie, as well as several notable additions, changes, and fixes to the project. The most important changes include the setup of the changelog system, breaking changes to existing properties, and new features added to the powerplatform resources. Fixes #460

Changelog System Setup:

• Added a CHANGELOG.md file and a header template to document all notable changes in the project. The changelog format is based on Keep a Changelog and adheres to Semantic Versioning. [1] [2]
• Configured Changie in .changie.yaml to manage changelog entries and their formats.
• Updated the development environment script to install Changie.

Breaking Changes:

• Changed powerplatform_solution.settings_file_checksum and powerplatform_solution.solution_file_checksum to use SHA256 instead of MD5. [1] [2]
• Updated powerplatform_tenant_settings.id to be set to the tenant ID instead of a random GUID, affecting existing resources.
• Removed powerplatform_solution.solution_name property as it is no longer required.

New Features:

• Added powerplatform_tenant and powerplatform_tenant_capcity data sources for tenant information and capacity details. [1] [2]
• Implemented user-defined timeouts for all resources.
• Introduced powerplatform_environment_group resource for creating environment groups.

Changes:

• Changed powerplatform_rest.expected_http_status and powerplatform_rest_query.expected_http_status types from []int64 to []int. [1] [2]

Fixes:

• Fixed timeout error in powerplatform_billing_policy.
• Fixed authentication error when calling powerplatform_rest or powerplatform_rest_query on newly created environments.