Add HttpWaitStrategy

[gossi]

As I'm porting a library over to elixir which uses testcontainers for testing, that library does use one resp. two wait strategies (depending on the impl).

• One is the Http Wait strategy, eg here is the node impl: https://github.com/testcontainers/testcontainers-node/blob/main/packages/testcontainers/src/wait-strategies/http-wait-strategy.ts
• In case of rust, also a duration wait (which the node one has as timeout option).

Thankfully there is a WaitStrategy protocol, I was able to build my own. I was wondering to push it upstream. I think an http client is then needed as a new dep? I'm using req as my http client.

If that idea is welcome and the dep is ok, I'd take a look if I can make it a bit more abstract and prepare a PR?

[jarlah]

The strategies are only developed to work and not polished. Your suggestions and PRs are welcomed if they solve a roblem and follow elixir conventions.

🙏