Add support for ParchmentJAM for migrating mapping data

[sciwhiz12]

This PR implements integration with JAMMER/JarAwareMapping in Compass, through the Parchment-specific integration application https://github.com/ParchmentMC/ParchmentJAM, which will resolve #19.

Testing this PR

Aside from configuring your Parchment repository to use this PR (preferrably, via includeBuild in the pluginManagement section of your settings.gradle¹), the following should be in the buildscript (either as part of other existing sections, or just copy-pasted at the very bottom):

dependencies {
    // ParchmentJAM, JAMMER integration for migrating mapping data 
    jammer 'org.parchmentmc.jam:jam-parchment:0.1.0'
}

compass {
    migration {
        targetVersion = '1.19.4' // Assuming the current version is 1.20.1
    }
}

You can determine if the migration system has been configured properly if the console output shows the path of versions which will be taken during migration (Setting up migration for the following versions in order: [...]), and the migrateData task is visible under the parchment group.

Some notes

• Yes, the target version can either be forwards or backwards of the current version.

• The final data is placed into the staging data environment (staging folder), and not directly into the production data environment (data folder). This allows the user a chance to determine changes between the new data and the old data, and make manual modifications if necessary.

  Once the user is satisfied with the changes (or this is run in automation), the promoteStagingToProduction task can be executed to move the data from staging to production.

• The migration can also be configured with the migration-targetVersion and migration-excludedVersion (comma-separated values) project properties.

---

Remaining work:

• Add more documentation to the migration configuration extension, and other classes.
• Allow configuring the migration options via project properties or environment variables.

Footnotes

1. For example, assuming that this PR is cloned to a directory Compass adjacent to your mappings repository, add the line includeBuild('../Compass') under the pluginManagement block of your mapping repository's settings.gradle file. Upon invoking Gradle (or refreshing your IDE's Gradle integration), you should see mentions of the Compass repository in the console output. ↩

[Lanse505]

Looks like Crap!
Rated: 18/3.17
Additional Notes: Not enough Bananas

[sciwhiz12]

Nothing pops out to me after -- checks timestamps -- a month of not looking at this code, and a quick test migration from 1.20.1 to 21w31a shows no visible explosions.