Detect and collect dependencies from gradle cache

Gradle maintains a build cache with a trove of package origins. This may not be super useful for a regular codebase scan, but is a great way to collect PURLs for indexing prior to matching.

There is a .module JSON file store in a path like this:
`gradle|.gradle`/`modules-2`/`files-2.1`/`maven dotted groupid, like "io.spring.gradle"`/`maven artifactid like "dependency-management-plugin"`/`version like 1.1.3`/`SHA1 of artifact like 3209385654a7e661d68de95a5ea8fc11d8ce015e`/`-.module like in dependency-management-plugin-1.1.3.module`

And that looks like that:
```JSON
{
"formatVersion": "1.1",
"component": {
"group": "com.google.android.material",
"module": "material",
"version": "1.9.0",
"attributes": {
"org.gradle.status": "release"
}
},
"createdBy": {
"gradle": {
"version": "7.3.3"
}
},
"variants": [
{
"name": "releaseVariantReleaseApiPublication",
"attributes": {
"org.gradle.category": "library",
"org.gradle.dependency.bundling": "external",
"org.gradle.libraryelements": "aar",
"org.gradle.usage": "java-api"
},
"dependencies": [
{
"group": "androidx.annotation",
"module": "annotation",
"version": {
"requires": "1.2.0"
}
},
{
"group": "androidx.appcompat",
"module": "appcompat",
"version": {
"requires": "1.5.0"
}
},
{
"group": "androidx.cardview",
"module": "cardview",
"version": {
"requires": "1.0.0"
}
},
{
"group": "androidx.coordinatorlayout",
"module": "coordinatorlayout",
"version": {
"requires": "1.1.0"
}
},
{
"group": "androidx.constraintlayout",
"module": "constraintlayout",
"version": {
"requires": "2.0.1"
}
},
........
}
],
"files": [
{
"name": "material-1.9.0.aar",
"url": "material-1.9.0.aar",
"size": 2202178,
"sha512": "7630aacb9e3073b2064397ed080b8d5bf7db06ba2022d6c927e05b7d53c5787d8153cd4a0360c36d52a79a7361e0b87f9d5fe856caf5ce5e7a89a9f30d9c7cce",
"sha256": "6cc2359979269e4d9eddce7d84682d2bb06a35a14edce806bf0da6e8d4d31806",
"sha1": "08f4a93a381be223a5bbaacd46eaab92381ab6a8",
"md5": "3287103cfb083fb998a35ef8a1983c58"
}
]
},
{
"name": "releaseVariantReleaseRuntimePublication",
"attributes": {
"org.gradle.category": "library",
"org.gradle.dependency.bundling": "external",
"org.gradle.libraryelements": "aar",
"org.gradle.usage": "java-runtime"
},
"dependencies": [
{
"group": "com.google.errorprone",
"module": "error_prone_annotations",
"version": {
"requires": "2.15.0"
}
},
{
"group": "androidx.annotation",
"module": "annotation",
"version": {
"requires": "1.2.0"
}
},
{
.................
````

See also:
- https://docs.gradle.org/current/userguide/build_cache.html
- https://docs.gradle.org/current/userguide/build_cache_use_cases.html
- https://stackoverflow.com/questions/23025433/how-to-clear-gradle-cache

See examples of these at:
- https://github.com/msdev27/CashCard/blob/799e8df1f9e7a9339d1bfe812a2ddc5bde1c3668/cashcard/gradle/caches/modules-2/files-2.1/io.spring.gradle/dependency-management-plugin/1.1.3/3209385654a7e661d68de95a5ea8fc11d8ce015e/dependency-management-plugin-1.1.3.module#L4
- https://github.com/goyoalucard/Farmacia/blob/627268aa05cfd41e274211da0091a7feb15a82cd/.gradle/7.5.1/caches/modules-2/files-2.1/org.jetbrains.kotlinx/kotlinx-coroutines-core-jvm/1.6.1/91d3217f26f78ef3b56e06b34b1233dab25c713/kotlinx-coroutines-core-jvm-1.6.1.module#L4
- https://github.com/liferay/liferay-binaries-cache-2020/blob/47003439ba0019bdbdbe2a15433d5dd3db5246c6/.gradle/caches/modules-2/files-2.1/com.liferay/com.liferay.gradle.plugins.source.formatter/5.2.69/e6e7283776c03991cfebb692ebd7d612de0852ff/com.liferay.gradle.plugins.source.formatter-5.2.69.module#L4