WithLogger is additive instead of replacing

Signed-off-by: Alex Suraci <suraci.alex@gmail.com>

oteltest: fail spans when tests are interrupted

Signed-off-by: Alex Suraci <suraci.alex@gmail.com>

LogConfig: support configuring attributes

dont need it yet, but someone might?

Signed-off-by: Alex Suraci <suraci.alex@gmail.com>

split RunSuite into RunTests and RunBenchmarks

also rename Middleware shorthand for consistency and update README

Signed-off-by: Alex Suraci <suraci.alex@gmail.com>

oteltest: bump testctx

Signed-off-by: Alex Suraci <suraci.alex@gmail.com>

update godoc, fix unit tests

Signed-off-by: Alex Suraci <suraci.alex@gmail.com>

Add logger support and refactor middleware handling

- Introduce `Logger` interface for flexible logging
- Add `WithLogger` method to support custom loggers
- Replace `Use()` with `Using()` for immutable middleware
- Remove `sync.Mutex` and simplify middleware management
- Update `New()` to accept initial middleware
- Enhance logging methods to support optional external logger
- Improve test coverage with logging test cases

Signed-off-by: Alex Suraci <suraci.alex@gmail.com>

add LICENSE and README

Signed-off-by: Alex Suraci <suraci.alex@gmail.com>

bump testctx

Signed-off-by: Alex Suraci <suraci.alex@gmail.com>

use real testctx module

Signed-off-by: Alex Suraci <suraci.alex@gmail.com>