feat: base image scratch => alpine:3

[mlajkim]

Description

Using alpine:3 has the following advantages:

• Be able to directly connect to the garm container (easier to manage applications)

Assignees

• Assignees is set

Type of changes

• Apply one or more labels of the following that fits:
  • bug: Bug fix
  • dependencies: Dependency upgrades
  • documentation: Documentation changes
  • enhancement: New Feature
  • good first issue: First contribution
  • logging: Log changes
  • refactor: Refactoring (no functional changes, no api changes)

Flags

- [ ] Breaks backward compatibility
- [ ] Requires a documentation update
- [ ] Has untestable code

---

Checklist

- [ ] Followed the guidelines in the CONTRIBUTING document
- [ ] Added prefix `[skip ci]`/`[ci skip]`/`[no ci]`/`[skip actions]`/`[actions skip]` in the PR title if necessary
- [ ] Tested and linted the code
- [ ] Commented the code
- [ ] Made corresponding changes to the documentation

Checklist for maintainer

- [ ] Use `Squash and merge`
- [ ] Double-confirm the merge message has prefix `[skip ci]`/`[ci skip]`/`[no ci]`/`[skip actions]`/`[actions skip]`
- [ ] Delete the branch after merge