Beam modernization at project 10-year mark

Summary This blog summarizes recent modernization efforts across the Apache Beam codebase mainly between Beam 2.68.0 and 2.75.0, such as major package upgrades, aligning APIs with new programming language standards, deprecations, etc. Note that new features are intentionally not included in the scope of this post, as it focuses on the modernization effort of existing components. Thank you to all contributors!