refactor: rename RDReaderView -> RDEpubReaderView, update pod config and docs

- Rename source module from RDReaderView to RDEpubReaderView
- Move all source files from Sources/RDReaderView/ to Sources/RDEpubReaderView/
- Update podspec: RDReaderView.podspec -> RDEpubReaderView.podspec
- Update Podfile, demo project, and CocoaPods config for new pod name
- Delete old RDReaderView pod support files from ReadViewDemo/Pods
- Add new RDEpubReaderView pod support files
- Update documentation (API ref, architecture, UML, conventions, etc.)
- Add FixedLayoutRotationTests
- Update .gitignore: exclude .DS_Store, manual unpack backups, _ssoft-output

ReadViewDemo/Podfile

@@ -3,7 +3,7 @@ platform :ios, '15.6'
 target 'ReadViewDemo' do
   # Comment the next line if you don't want to use dynamic frameworks
   use_frameworks!
-  pod 'RDReaderView', :path => '..'
+  pod 'RDEpubReaderView', :path => '..'
 
 end