CB-12935 Run paramedic builds on Travis

[alsorokin]

Platforms affected

Android, iOS

What does this PR do?

https://issues.apache.org/jira/browse/CB-12935
Adds paramedic builds to Travis CI runs.

What testing has been done on this change?

A test run on my own Travis CI account.

Checklist

• Reported an issue in the JIRA database
• Commit message follows the format: "CB-3232: (android) Fix bug with resolving file paths", where CB-xxxx is the JIRA ID & "android" is the platform affected.
• Added automated test coverage as appropriate for this change.

[filmaj]

Parametric builds seem OK! But env vars still seem off :(

[alsorokin]

Encrypted vars are disabled for PR builds. We'll have to find another way around (make them unencrypted?)