Support Gradle build cache when using absolute path references

[erichaagdev]

This PR marks several file/directory task input properties of the GenerateTask as either @InputFile or @InputDirectory and @PathSensitive(PathSensitivity.RELATIVE).

This enables the following:

• GenerateTask will not be considered UP-TO-DATE when the contents of one of these files or directories changes
• GenerateTask will reuse outputs from the build cache when using absolute file path property values and when running from a different directory

fixes #10214
fixes #11808
fixes #13663

Gradle Build Scan: https://scans.gradle.com/s/dp2plkit3wcxo

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[erichaagdev]

I'm not sure why CI failed, but it seems unrelated to my changes.

[erichaagdev]

@wing328 would you be able to look at this? Thank you!

[wing328]

Restarted the job and all tests passed