[CI] Add GitHub Action to push development docker images

[niccoloraspa]

What is the purpose of the change

This PR creates a GitHub Action to push development docker images on:

1. Every new tag containing a release candidate (e.g. v1.2.3-rc4).
   osmolabs/osmosis-dev:1.2.3-rc4 is pushed.

2. Every new commit to the main branch
   osmolabs/osmosis-dev:main-{SHORT_SHA}-$(date +%s) is pushed.

3. Every new commit to a development branch vN.x (e.g. v1.x)
   osmolabs/osmosis-dev-v1.x:{SHORT_SHA}-$(date +%s) is pushed.

Note: $(date +%s) will be used later as an index to sort the tags chronologically in the docker registry to get the latest one.

All the images above support only linux/amd64 (not linux/arm64) so they can be built a lot faster.
All the images are based on an alpine image for easy debugging (you would always have a shell to exec inside the container)

Context

This is the first step for the automatic creation of devnets.
On every new commit to a vN.x branch, a new vanilla (or state-exported) testnet will be launched.

Brief Changelog

• Add GitHub Action to push development docker images

Testing and Verifying

Ran a test on the osmosis-ci-repo.

Documentation and Release Note

• Does this pull request introduce a new feature or user-facing behavior changes? no
• Is a relevant changelog entry added to the Unreleased section in CHANGELOG.md? no
• How is the feature or change documented? not applicable

[ValarDragon]

Awesome!
utACK