drop docker from docs and makefile (#1087)

README.adoc

@@ -61,7 +61,7 @@ There are multiple Makefile targets that will execute the e2e tests, they just d
 * `make test-e2e-host-local` - this target clones only the https://github.com/codeready-toolchain/member-operator[member-operator] repo and builds an image from it. For host-operator, it builds the image from `../host-operator` directory. These images deploys to OpenShift and runs e2e tests against them.
 
 The e2e tests will take care of creating all needed namespaces with random names (or see below for enforcing some specific namespace names).
-It will also create all required CRDs, role and role bindings for the service accounts, build the Docker images for both operators and push them to the OpenShift container registry. Finally, it will deploy the operators and run the tests using the operator-sdk.
+It will also create all required CRDs, role and role bindings for the service accounts, build the container images for both operators and push them to the OpenShift container registry. Finally, it will deploy the operators and run the tests using the operator-sdk.
 
 
 NOTE: you can override the default namespace names where the end-to-end tests are going to be executed - eg.: `make test-e2e HOST_NS=my-host MEMBER_NS=my-member` file.
@@ -165,7 +165,7 @@ NOTE: By default, `SECOND_MEMBER_MODE` is set to false.
 * Get a cluster and setup the following env vars
 ** `export QUAY_NAMESPACE=<your-quay-namespace>`
 ** `export KUBECONFIG=<location-to-kubeconfig>`
-* Run `docker login quay.io`
+* Run `podman login quay.io`
 * Create https://github.com/codeready-toolchain/toolchain-infra/tree/master/config/oauth[IdP]
 * If you need to change any of the default configuration, modify the ToolchainConfig in https://github.com/codeready-toolchain/toolchain-e2e/blob/master/deploy/host-operator/dev/toolchainconfig.yaml[deploy/host-operator/dev/toolchainconfig.yaml]
 * To set working notification/verification secrets, modify them in https://github.com/codeready-toolchain/toolchain-e2e/blob/master/deploy/host-operator/dev/secrets.yaml[deploy/host-operator/dev/secrets.yaml]

quay.adoc

@@ -7,7 +7,7 @@ There is a set of images that is built and pushed to quay repositories while dep
 . Make sure you have set the _QUAY_NAMESPACE_ variable: +
 `export QUAY_NAMESPACE=<quay-username>`
 . Log in to quay.io using +
-`docker login quay.io`
+`podman login quay.io`
 * Make sure that these repositories exist on quay.io and the visibility is set to `public` for all of them:
  * https://quay.io/repository/<quay-username>/host-operator
  * https://quay.io/repository/<quay-username>/host-operator-bundle

required_tools.adoc

@@ -6,7 +6,6 @@ NOTE: Follow the installation instructions https://sdk.operatorframework.io/docs
 * sed
 * yamllint
 * jq
-* podman +
-NOTE: If you need to use docker, then run the make targets with this variable set: `IMAGE_BUILDER=docker`.
+* podman
 * opm v1.26.3 +
 NOTE: To download the Operator Registry tool use either https://github.com/operator-framework/operator-registry/releases or https://mirror.openshift.com/pub/openshift-v4/x86_64/clients/ocp/. The version should correspond with the OpenShift version you are running. To confirm that the Operator Registry tool is installed correctly: `$ opm version`