TST: Move Continuous Deployment to Azure, depricate Travis

[CameronTStark]

Is your feature request related to a problem? Please describe.
Having multiple CI/CD solutions require duplicate system knowledge and maintenance.

Describe the solution you'd like
Move all CD to Azure from Travis and remove its config file.

Describe alternatives you've considered
Moving everything to GitHub Actions. To my knowledge there is less parallelism so we'd suffer a loss in speed comparatively with Azure Pipelines.

Additional context
When releasing 0.7.0 I found that having the CI and CD overlapping in some areas and separate in some areas confusing and I also am late to the game in learning Travis. Since 90% of the testing seems to be done on Azure Pipelines I felt motivated to move towards 100% so we would have less things to look at and maintain.

The main aspects that need to be moved are:

• Deployment to PyPI
• py35-min testing

Please let me know if I'm missing a valuable aspect of Travis would be missed with deprecating Travis. Thanks!

[CameronTStark]

Another compelling reason to include this is that it will do a final test run in Azure after tagging. Currently Travis only picks up on the tag and ultimately publishes it to PyPI but it only executes the py35-min test which may not catch deprecation errors for the new version. This would then necessitate a quick version bump to address those missed functions that should have been deprecated.

I witnessed this just now when creating v0.7.2-rc.1 and found that Azure had not run but Travis had.

[wholmgren]

github actions is the cool CI now. Its configuration and interface is similar to azure pipelines but in my limited experience better in every way.

If I recall correctly, github actions had just come out when we switched to azure pipelines and it didn't seem well documented enough or proven enough to use. I followed the lead of other projects (pandas in particular) in implementing azure, but they've now switched to github actions. pvlib/pvanalytics has been using github actions too.