Add GitHub Actions workflows for build automation

[cartland]

trafficstars

This commit adds two new GitHub Actions workflows:

• build-pose.yml: Builds the NeuralNetworksSamplesPoseEstimationApp.
• build-sequence.yml: Builds the NeuralNetworksSamplesSequenceApp.

These workflows automate the build process for the specified applications, including setting up the JDK, Gradle, and building the app. The workflows are triggered on push and pull request events to the main branch, as well as workflow_dispatch.