Initialize default content handlers using updated API
Refactor client asset management methods from `Theme` to `Component`
Refactor content handler client asset loading
Refactor image handler definition
Refactor content handler registration/update methodology

* Use single `extend_content_handler()` method
Merge branch 'chdlr-registration' into develop
Refactor template tag asset management

* Registration
* Build client output
Refactor default template tag handler definitions
Refactor template tag handler client registration

* Use single `extend_template_tag_handler()` method for adding/updating handlers
Merge branch 'tmptag-registration' into develop
THM: Clean up code

* Remove deprecated methods
* Remove unused code
* Organization
Merge branch 'thm-cleanup' into develop
Add support for third-party matching for `Image` content handler
Merge branch 'chdl-image-hooks' into develop
Utilities: Enable relative path retrieval & URI check

* Add: `is_uri()`
* Add: `get_relative_path()`
* Update: `get_path_base()`
* Update: `get_file_path()`
Base Object: Optimize path normalization in `get_file()`
Themes: Allow relative asset paths when registering themes
Merge branch 'thm-api-assets' into develop
THM: Remove default layout (uses parent's layout)
THM-Default: Update title margins