Allow to select redis image

[Dudesons]

Description

Bitnami dockerhub repository drop images at least for the redis repository: https://hub.docker.com/r/bitnami/redis#%EF%B8%8F-important-notice-upcoming-changes-to-the-bitnami-catalog

So the goal of this PR is to be able to select an image with a default to the redis official image.

Changes include

• Bugfix (non-breaking change that solves an issue).
• Hotfix (change that solves an urgent issue, and requires immediate attention).
• New feature (non-breaking change that adds functionality).
• Breaking change (change that is not backwards-compatible and/or changes current functionality).
• Documentation update (change added to any kind of documentation).

Checklist

• I have assigned this PR to myself.
• I have added at least 1 reviewer.
• I have added the relevant labels.
• I have updated the official documentation.
• I have added sufficient documentation in code.

Testing

• I have tested this code with the official test suite.
• I have tested this code manually.

Manual tests

start server: dagger call server up
output:

▶ connect 0.2s
▶ load module: . 0.8s
● parsing command line arguments 0.0s

● redis: Redis! 0.4s
▶ .server: Container! 2.1s
▼ .up: Void 3m14s
┃ 10:44:46 INF tunnel started port=6379 protocol=tcp http_url=http://localhost:6379 description="tunnel 0.0.0.0:6379 -> o7osik9ndt5dc.te3k6beq7
┃ 0s.dagger.local:6379"                                                                                                                        

12:47:58 WRN canceling... (press again to exit immediately)

set key: dagger call cli --server=tcp://localhost:6379 set --key=foo --value=bar
output:

▶ connect 0.2s
▶ load module: . 3.5s
● parsing command line arguments 1.7s

● redis: Redis! 0.4s
▶ .cli(
  ┆ server: Host.service(ports: [{frontend: 6379, backend: 6379, protocol: TCP}], host: "localhost"): Service!
  ): RedisCli! 0.4s CACHED
▶ .set(key: "foo", value: "bar"): Container! 0.8s

Container@xxh3:381873ea48915acc

get key: dagger call cli --server=tcp://localhost:6379 get --key=foo
output:

▶ connect 0.2s
▶ load module: . 0.5s
● parsing command line arguments 1.6s

● redis: Redis! 0.4s
▶ .cli(
  ┆ server: Host.service(ports: [{frontend: 6379, backend: 6379, protocol: TCP}], host: "localhost"): Service!
  ): RedisCli! 0.4s CACHED
▶ .get(key: "foo"): String! 0.8s

bar

Documentation update

redis readme