Release 7.4.0 version of the che-plugin-registry

[ibuziuk]

What does this PR do?

Release 7.4.0 version of the che-plugin-registry - eclipse-che/che#15111

• Bumping VERSION file
• Adding '7.4.0' versions for che-theia & machine-exec
• Setting 'latest' version for che-theia and machine-exec plugins to '7.4.0'
• Setting '7.4.0' version for container runtime images of the che remote plugins - find . -name '*.yaml' -exec sed -i -e 's/:next/:7.4.0/g' {} ;