WT-369 PROJECT.yaml and its products:

• PROJECT.yaml -> PROJECT.yaml.txt
• ./docs/README.md -> README.md.txt
• ./docs/README.md -> README.html
• ./docs/CHANGELOG.md -> CHANGELOG.md.txt
• ./docs/CHANGELOG.md -> CHANGELOG.html
• ./docs/METADATA-1.yaml -> METADATA-1.yaml.txt
• ./docs/METADATA.yaml -> METADATA.yaml.txt
• ./docs/METADATA-1.md -> METADATA-1.md.txt
• ./docs/METADATA-1.md -> METADATA-1.html
• ./docs/METADATA.md -> METADATA.md.txt
• ./docs/METADATA.md -> METADATA.html
• ./docs/METADATA-1.mk -> METADATA-1.mk.txt
• ./docs/METADATA.mk -> METADATA.mk.txt