Tidy imports for controller

There were some duplicate aliases and imports which have been
consolidated.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Add range checking for endpoints

This could fail when endpoints are removed during a scale down
operation.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Move to Go Client 1.17 for Kubernetes

As per change made to openfaas-operator, this bumps up the Go
client for Kubernetes to 1.17.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Update Travis runtime version

The Travis runtime version has been updated to match the version
of Go in the Dockerfile (1.13)

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Update faas-provider to 0.14.0

**What**
- Update the version of faas-provider
- Update the info handler to use the renamed `InfoResponse` struct and
  add a basic test for the handler

Signed-off-by: Lucas Roesler <[email protected]>

Change namespaces handler status code

Changing namespaces handler status code to return
200 when requested instead of 202

Signed-off-by: Martin Dekov <[email protected]>

Move proxy to k8s package

This commit moves the proxy to the k8s package so that it can be
shared with the openfaas-operator.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Move LogRequestor into k8s package

This allows the code to be vendored into the openfaas-operator.

Tested with go build.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <[email protected]>

Improve secret update error log message

Signed-off-by: Lucas Roesler <[email protected]>

Load env process value into function status

**What**
- Copies the `readFunction` method as `AsFunctionStatus` in the k8s package
  for loading a function Deployment into a FunctionStatus struct. This
  includes new tests for the method

Signed-off-by: Lucas Roesler <[email protected]>