feat: NetBox 4.5.x support

[mfiedorowicz]

This pull request updates the build and test infrastructure to better support multiple NetBox versions, particularly v4.5.x and v4.4.x, and consolidates Docker configuration for easier maintenance. The changes also introduce improved environment variable handling and update documentation to reflect new version compatibility.

Build & Docker infrastructure updates:

• Consolidated Docker Compose files into a shared docker/common directory, using variable substitution for NetBox versions and paths, which simplifies maintenance and supports multiple NetBox minor versions more easily. (Makefile, docker/common/docker-compose.yaml, docker/common/docker-compose.test.yaml, [1] [2] [3]
• Updated the Makefile to default to NetBox v4.5.0 and to use the new shared Docker Compose files, with improved handling of version variables and paths. (Makefile, MakefileL7-R54)
• Changed volume mount paths in Docker Compose files to use shared configuration and coverage directories, further improving consistency across versions. (docker/common/docker-compose.yaml, [1] [2] [3] [4]

Testing & CI improvements:

• Updated GitHub Actions workflow to test against NetBox v4.5.0 and v4.4.10 (removing v4.2.3), ensuring CI coverage for the latest supported versions. (.github/workflows/lint-tests.yml, .github/workflows/lint-tests.ymlL29-R29)

Configuration & security:

• Added support for API token peppering by introducing the API_TOKEN_PEPPER_1 environment variable and corresponding logic in the configuration, improving security for API tokens. (docker/common/netbox/env/netbox.env, docker/common/netbox/configuration/configuration.py, [1] [2]

Documentation:

• Updated the README to document compatibility with NetBox v4.5.0 and plugin version 1.7.0. (README.md, README.mdR24)