Add release process script

[andreyvelich]

Fixes: #1466.

I added Katib release script.
In Makefile we currently have:

1. push-latest to publish images to the registry with the latest and commit tags from the master branch.
2. push-tag to publish image to the registry with the release and commit tags from the release branch.
3. release to make a new Katib release.

I changed build.sh and push.sh scripts to use them when publishing latest images and release images.

Release script follows this (e.g. Branch = release-0.11, Tag = v0.11.0):

1. Clone Katib repo to the temp dir.
2. Create a new branch (release-0.11), if it doesn't exist or use the existing branch.
3. Change image tags to the v0.11.0 in the Katib installs.
4. Publish Katib SDK with version - 0.11.0.
5. Commit changes in the release-0.11 branch and add v0.11.0 tag to this commit.
6. Publish Katib images with 2 tags: v1beta1-<commit-SHA> and v0.11.0.
7. Push release-0.11 branch and v0.11.0 tag to the upstream.

Please take a look.
/assign @yanniszark @gaocegege @johnugeorge

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[andreyvelich]

/hold for the review

[gaocegege]

/lgtm

[andreyvelich]

After discussion with @yanniszark, we decided to leave only one tag in Push and Build scripts and run them for the release tag and commit tag.

[yanniszark]

Thanks @andreyvelich!
/lgtm

[johnugeorge]

/lgtm

[google-oss-robot]

New changes are detected. LGTM label has been removed.

[andreyvelich]

Thanks for the review!
/hold cancel

[andreyvelich]

/retest