Update and modernize all samples

[ceyhun-o]

This PR:

• Rebrands all samples from THEOplayer to Dolby OptiView including logos, colors and styling. They are now aligned with the iOS samples.
• Modernizes all samples to Jetpack Compose. So the XML layouts are (almost) all gone! All samples now use Open Video UI.
• Bumps all dependencies, moves all samples to Java 17 and Gradle 9.
• Expands the existing Open Video UI sample into a theme showcase with 7 custom UIs!
• Adds 4 new samples; OptiView Ads, Millicast, THEOlive and a localization sample to demonstrate Open Video UI's localization capability.
• Moves the PiP handling sample a native PiP implementation logic (using enterPictureInPictureMode() instead of the PiP APIs from the player)

Some other minor, but good changes:

• All application manifests are now structured in a consistent way across all samples with no deprecated Android APIs in between. The apps also no longer have layout restrictions either since these are now ignored.
• None of the samples now have any deprecated Java/THEOplayer APIs (as of now 🤞).
• All samples use the common SourceManager.kt to set sources.
• Updated all READMEs.