Improve detection results from liquibase

### Description

1. On scanning https://github.com/liquibase/liquibase/tree/v4.19.0/liquibase-dist/src/main/archive/licenses/commercial/README.rst we detect the 3 main license references correctly:

- apache-2.0
- lgpl-2.1
- agpl-3.0

But this could be better in the following ways:

- Both `agpl-3.0` and `agpl-3.0-plus` are in the license expression, should be resolved to only `agpl-3.0`
- license expression can be simplified
- We do not detect anything on the line: `Liquibase License Information (Used by Liquibase Commercial)` though this doesn't have any of the commercial license terms just a vague reference.

Maybe this should be detected as a `commercial-license` reference?

2. There https://github.com/liquibase/liquibase/blob/v4.19.0/liquibase-dist/src/main/archive/licenses/commercial/Liquibase%20Pro%20EULA%20Software%20License%20Subscription%20and%20Support%20Agreement.txt:

where we were detecting just `unknown` before. But now we are detecting `unknown-license-reference`, `proprietary-license`, `unknown` (and an `apple-attribution-1997` which is a heuristics bug, this should be filtered out)

3. There's also `licenses/oss/futc.txt`, `licenses/oss/ipla.txt`, `licenses/oss/README.rst` where we can do improvements at https://github.com/liquibase/liquibase/tree/v4.19.0/liquibase-dist/src/main/archive/licenses/oss

### System configuration

> For bug reports, it really helps us to know:

* What OS are you running on? (Windows/MacOS/Linux) Ubuntu
* What version of scancode-toolkit was used to generate the scan file? v31.2.4 and v32.0.0rc1
* What installation method was used to install/run scancode? (pip/source download/other) source archive

### Scan Results

[liquibase-licenses-v32.0.rc1.json.txt](https://github.com/nexB/scancode-toolkit/files/10663305/liquibase-licenses-v32.0.rc1.json.txt)

[liquibase-licenses-v31.2.4.json.txt](https://github.com/nexB/scancode-toolkit/files/10663300/liquibase-licenses-v31.2.4.json.txt)

Also scans on this file: https://github.com/tensorflow/tensorflow/blob/master/tensorflow/lite/java/ovic/Winner_OSS_Template.md

[tensorflow-v31.2.4.json.txt](https://github.com/nexB/scancode-toolkit/files/10663307/tensorflow-v31.2.4.json.txt)
[tensorflow-v32.0.0rc1.json.txt](https://github.com/nexB/scancode-toolkit/files/10663308/tensorflow-v32.0.0rc1.json.txt)