added support to create package alias #200

[boussaffawalid]

Changelog: (Feature | Fix | Bugfix): Describe here your pull request

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[uilianries]

@boussaffawalid Could you explain why do you need this feature?

[boussaffawalid]

I think it is very handy to provide an alias to the latest built package.
In our ci we deduct the conan package version from the git commit sha, which create a new package version for every commit.

For example:

• commit c1 will create a package pkg_name/1.0.0-c1@me/stable
• commit c2 will create a package pkg_name/1.0.0-c2@me/stable
  .....

The idea is to have an alias package pkg_name/latest@me/stable that always point to the latest package.

What do you think ?