sdk/log: Add FilterProcessor and EnabledParameters (#6317)

Per
https://github.com/open-telemetry/opentelemetry-go/pull/6271#issuecomment-2657554647

> We agreed that we can move `FilterProcessor` directly to `sdk/log` as
Logs SDK does not look to be stabilized soon.

- Add the possibility to filter based on the resource and scope which is
available for the SDK. The scope information is the most important as it
gives the possibility to e.g. filter out logs emitted for a given
logger. Thus e.g.
https://github.com/open-telemetry/opentelemetry-specification/issues/4364
is not necessary. See
https://github.com/open-telemetry/opentelemetry-specification/pull/4290#discussion_r1927546170
for more context.
- It is going be an example for
https://github.com/open-telemetry/opentelemetry-specification/issues/4363

There is a little overhead (IMO totally acceptable) because of data
transformation. Most importantly, there is no new heap allocation.

```
goos: linux
goarch: amd64
pkg: go.opentelemetry.io/otel/sdk/log
cpu: 13th Gen Intel(R) Core(TM) i7-13800H
                 │   old.txt   │                 new.txt                  │
                 │   sec/op    │     sec/op      vs base                  │
LoggerEnabled-20   4.589n ± 1%   319.750n ± 16%  +6867.75% (p=0.000 n=10)

                 │   old.txt    │             new.txt             │
                 │     B/op     │     B/op       vs base          │
LoggerEnabled-20   0.000Ki ± 0%   1.093Ki ± 13%  ? (p=0.000 n=10)

                 │  old.txt   │            new.txt             │
                 │ allocs/op  │ allocs/op   vs base            │
LoggerEnabled-20   0.000 ± 0%   0.000 ± 0%  ~ (p=1.000 n=10) ¹
¹ all samples are equal
```

`Logger.Enabled` is still more efficient than `Logger.Emit` (benchmarks
from https://github.com/open-telemetry/opentelemetry-go/pull/6315).

```
goos: linux
goarch: amd64
pkg: go.opentelemetry.io/otel/sdk/log
cpu: 13th Gen Intel(R) Core(TM) i7-13800H
BenchmarkLoggerEmit/5_attributes-20               559934              2391 ns/op           39088 B/op          1 allocs/op
BenchmarkLoggerEmit/10_attributes-20             1000000              5910 ns/op           49483 B/op          5 allocs/op
BenchmarkLoggerEnabled-20                        1605697               968.7 ns/op          1272 B/op          0 allocs/op
PASS
ok      go.opentelemetry.io/otel/sdk/log        10.789s
```

Prior art:
- https://github.com/open-telemetry/opentelemetry-go/pull/6271
- https://github.com/open-telemetry/opentelemetry-go/pull/6286

I also created for tracking purposes:
- https://github.com/open-telemetry/opentelemetry-go/issues/6328

sdk/log/processor.go

@@ -13,8 +13,7 @@ import (
 // or with other methods. It is the responsibility of the Processor to manage
 // this concurrency.
 //
-// See [go.opentelemetry.io/otel/sdk/log/internal/x] for information about how
-// a Processor can be extended to support experimental features.
+// See [FilterProcessor] for information about how a Processor can support filtering.
 type Processor interface {
 	// OnEmit is called when a Record is emitted.
 	//
@@ -30,11 +29,11 @@ type Processor interface {
 	// Handler.
 	//
 	// The SDK invokes the processors sequentially in the same order as
-	// they were registered using [WithProcessor].
+	// they were registered using WithProcessor.
 	// Implementations may synchronously modify the record so that the changes
 	// are visible in the next registered processor.
-	// Notice that [Record] is not concurrent safe. Therefore, asynchronous
-	// processing may cause race conditions. Use [Record.Clone]
+	// Notice that Record is not concurrent safe. Therefore, asynchronous
+	// processing may cause race conditions. Use Record.Clone
 	// to create a copy that shares no state with the original.
 	OnEmit(ctx context.Context, record *Record) error