enhance: Add comprehensive .gitignore for deb-mock project

- Add mock-specific build artifacts (chroot/, mock-*, mockroot/)
- Include package build files (*.deb, *.changes, *.buildinfo)
- Add development tools (.coverage, .pytest_cache, .tox)
- Include system files (.DS_Store, Thumbs.db, ._*)
- Add temporary and backup files (*.tmp, *.bak, *.backup)
- Include local configuration overrides (config.local.yaml, .env.local)
- Add test artifacts and documentation builds
- Comprehensive coverage for Python build system project

This ensures build artifacts, chroot environments, and development
tools are properly ignored in version control.

docs/Feature-package-managers.md

@@ -0,0 +1,39 @@
+---
+layout: default
+title: Feature DNF
+---
+## DNF
+
+This is default package manager for mock. You can enforce it (e.g. in older Mock) using>
+
+```
+config_opts['package_manager'] = 'dnf'
+```
+
+## YUM
+
+Yum is still used in RHEL 7 and olders. You can enable it using
+
+```
+config_opts['package_manager'] = 'yum'
+```
+
+## MicroDNF
+
+MicroDNF is written in C and does not need Python. It is present in minimal OCI containers. It can be enabled using:
+
+```
+config_opts['package_manager'] = 'microdnf'
+```
+
+However, MicroDNF still [does not have `buildep` command](https://github.com/rpm-software-management/microdnf/issues/82). The current implementation still installs DNF (using microdnf) and use DNF to query the build deps.
+
+You can use following options in the config:
+```python
+config_opts['microdnf_command'] = '/usr/bin/microdnf'
+# "dnf-install" is special keyword which tells mock to use install but with DNF
+config_opts['microdnf_install_command'] = 'dnf-install microdnf dnf dnf-plugins-core distribution-gpg-keys'
+config_opts['microdnf_builddep_command'] = '/usr/bin/dnf'
+config_opts['microdnf_builddep_opts'] = []
+config_opts['microdnf_common_opts'] = []
+```