Update README and examples to reflect v1 changes

[aulorbe]

Problem

We are close to launching v1! With it, our README needs a facelift. Here is that facelift 💅.
We have also updated the SDK version, user-agent string, and the examples package.

Asana tix:

• Audrey: https://app.asana.com/0/1203260648987893/1207042384514994/f
• Rohan: https://app.asana.com/0/1203260648987893/1206745140276838/f

Solution

Update README, user-agent string, and examples for v1 java SDK. We have currently removed the UpsertsAndQueriesConcurrentExample example but in upcoming PR's, we will like to add it back.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Infrastructure change (CI configs, etc)
• Non-code change (docs, etc)
• None of the above: (explain here)

[austin-denoble]

Overall looks good, I'm not sure if the version comment in the CHANGELOG file needs to be updated to v1.0.0 though.