Deprecate older versions of scancode

### Description

ClearlyDefined supports multiple versions of scancode-toolkit. Many of the versions use a different data format requiring special processing. The code would be cleaner if fewer versions were supported. However, removing versions requires data in the older format to be reharvested.

This issue proposes deprecating and later removing support for older versions of ScanCode.

Deprecation vs. Removal: Typically when removing functionality, it is deprecated in the current major release and removed in the next major release. This is consistent with the requirements of [semantic versioning](https://semver.org).

Considerations:
* When support for a version is added, existing data generated by older versions remain unchanged. As such, processing of the format for the older version needs to continue.
* Removing support for a version requires re-harvesting of dependencies with data in the older format. Need an estimate of the number of dependencies that would be impacted if versions were removed.

Questions:
* How long should a version be supported?
* How much processing will be required to reharvest?

### Scancode Versions

Supported now

| version | release date | processing approach | supported? |
| --- | --- | --- | --- |
| < 2.2.1 | | | -- |
| 2.2.1 | 2017-10-05 | 2.2.1 processing | YES |
| 2.9.1 | 2018-03-22 | 2.9.1 processing | YES |
| 2.9.2 | 2018-05-08 | 2.9.2 processing | YES |
| 2.9.8 | 2018-12-12 | same as 2.9.2 processing | YES |
| 3.0.0 | 2019-02-14 | 3.0.0 processing | YES |
| 3.0.2 | 2019-02-15 | same as 3.0.0 processing | YES |
| 30.1.0 | 2021-09-25 | 30.1.0 processing | YES |
| 32.0.8 | 2023-10-16 | This will require different processing. | in progress |

_NOTES: Versions not on this list indicates that version was never used by ClearlyDefined. As such, there are no curations in the format specific to one of those versions. And no processing was put in place for those versions._