SparkAuronConfiguration does not work well with unit tests

**Describe the bug**
The configuration component is:
- Backed by a global singleton and process-wide mutable state.
- Read indirectly through static helpers instead of via injected or scoped configuration.
- Not aligned with the usual test utilities (e.g., per-test overrides / context-local configs).
- This makes it difficult for unit tests to toggle config in a safe, local way.

Ideally, it should look like the utility provided by AuronConverters.

```scala
private lazy val foo: Boolean =
AuronConverters.getBooleanConf(
"spark.auron.foo",
defaultValue = false)
```

**To Reproduce**
1. Write code that reads a configuration flag via the global config helper.
2. In a unit test, try to change behavior by setting that config just for the test (e.g., via a per-test helper or context API).
3. The code still reads from the global state.

**Expected behavior**
Configuration should be:
- Scoped (per test, per request, or per session), not global.
- Injectable or overridable at the boundary of the component under test.
- Compatible with normal testing patterns (e.g., fixtures, context managers, withConfig { ... }-style APIs).

**Screenshots**

**Additional context**

A more test-friendly design would centralize config in a small object passed into components (or read from a clearly scoped context), so each test can construct the configuration it needs without mutating global state.