Per https://stackoverflow.com/a/56664610/132047

Bumps [jackson-databind](https://github.com/FasterXML/jackson) from 2.9.10 to 2.9.10.1.
- [Release notes](https://github.com/FasterXML/jackson/releases)
- [Commits](https://github.com/FasterXML/jackson/commits)
Signed-off-by: Ndependabot[bot] <support@github.com>

| Library            | From     | To        |
| :----------------- | :------- | :-------- |
| animal.sniffer     |  1.14    |  1.18     |
| assertj            |  1.7.0   |  3.13.2   |
| guava              |  19.0    |  28.1-jre |
| jackson            |  2.9.8   |  2.9.10   |
| jaxb               |  2.2.12  |  2.3.1    |
| jsoup              |  1.7.3   |  1.12.1   |
| kotlin             |  1.3.10  |  1.3.50   |
| kotlinx.coroutines |  1.1.0   |  1.3.2    |
| okhttp             |  3.14.0  |  3.14.4   |
| protobuf           |  3.5.0   |  3.10.0   |
| rxjava             |  1.3.0   |  1.3.8    |
| scala              |  2.12.4  |  2.13.1   |

The XML format changed again, so I decided to switch us to Checksytle's
curated 'Google Style Guide' format which seems like a reasonable
enough default for us.

https://checkstyle.sourceforge.io/google_style.html

Also fix some Javadoc errors and ensure Javadoc (and source) jar generation is tested on CI.

It wasn't used for anything interesting and I prefer not having it around to tempt contributors to add new usages of it.

This is built in a way such that its absence from the classpath will not cause failures.

Use get instead of parse for HttpUrl and MediaType where valid input is always required.