* Update dependencies in prep for Composer 2.x.
* Rollback jetpack autoloader update.
* Restore range versions for composer dependencies, regenerate lock with Composer 1.x.
* Fix PSR-4 Classes (https://github.com/woocommerce/woocommerce-admin/pull/5473)
* PSR-4 class names need to match their filename.
Remove underscores in classnames.
* Fix reported class name in deprecation notice.
* Fix comments.
* We don't need composer dependencies in core WC test setup.
* Update composer lockfile using version 2.x.
* Temporarily turn off error display.
Function deprecation notices are breaking tests.
* Rename admin notes classes and file names to fit conventions
* Use a facade class that adds deprecation warnings to each function call
* Tidy up after rebase
Co-authored-by: Rebecca Scott <me@becdetat.com>