[DPE-3702] Add snap aliases for MySQL server / Router (#417)

* add snap aliases

* generate alias only after workload install

* fix spacing

* fix spacing again

* update tests

* fix linting and test

* fetch lib v2

* update charm install test to include aliases check

* fix linting

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Co-authored-by: Ubuntu <[email protected]>
Co-authored-by: Ubuntu <[email protected]>

Author: 3 people