Add the ability to manually include OSS licenses

[wseemann]

Hello, this is a great library! I noticed the oss-licenses-plugin didn't have the ability to add licenses manually so I added that functionality. To test this PR:

1. Create custom_dependencies.json under res/raw
2. Add entries any number of manual entries in the following JSON format:

[
  {
    "group": "",
    "version": "1.2.0",
    "fileLocation": "custom",
    "name": "Speex",
    "license": "https://www.speex.org/docs/manual/speex-manual/node15.html#sec:Speex-License"
  },
  {
    "group": "some.group",
    "version": "1.2.3",
    "fileLocation": "custom",
    "name": "Some Library",
    "license": "Some Text or URL"
  }
]

3. Build and run the app like usual, enjoy

Let me know if you have any revisions!

[wseemann]

FYI, I just filled out the Google CLA

[juliankotrba]

Hey @wseemann, just FYI, there is already a similar open PR for supporting third party licenses. However, the linked PR is already open for quite some time - still waiting for a maintainer's review. Fingers crossed that one the the PRs get merged anytime soon.

[wseemann]

open PR

Thank you, I'm aware.

[wseemann]

Closing out this MR due to inactivity.