Before change
```
⇶ golangci-lint run --disable-all --no-config --enable=staticcheck | ack SA6005
builder/profitbricks/step_create_server.go:254:22: SA6005: should use strings.EqualFold(a, b) instead of strings.ToLower(a) == strings.ToLower(b) (staticcheck)
builder/oneandone/config.go:97:7: SA6005: should use strings.EqualFold(a, b) instead of strings.ToLower(a) == strings.ToLower(b) (staticcheck)
builder/vmware/common/driver_parser.go:1199:7: SA6005: should use strings.EqualFold(a, b) instead of strings.ToLower(a) == strings.ToLower(b) (staticcheck)
```
After change
```
⇶ golangci-lint run --disable-all --no-config --enable=staticcheck | ack SA6005
```
Refactor step_export and the driver interface to move the ovftool call
into the vmware driver. This refactor allows us to add meaningful tests
to step_export, which I have also added here.
* add progress tracker to vmware-esx iso upload. Add colored prefix to tracker to make it clear which build a tracker belongs to.
* fix mock; fix tests
* add kex algorithm option to ssh config
* regenerate code
* This commit fixes old vmware acceptance tests that have not been run in some time. It does this in two parts:
1) It modifies the minimal vmware build configuration to use a custom kex algorithm, which enables the ssh connection to succeed.
2) It modifies logic in reading and defaulting hardware config values, which was crashing.
3) It adds a new acceptance test with a preseed file to test loading from an http directory.