Add an init phase to detect skaffold errors even before skaffold runner is created.

[tejal29]

Relates to #4692

Add distinct error codes to reduce "UNKNOWN_ERROR" when skaffold was not able to create a runner.
where phase= "UNKNOWN", and error code is "ERROR"
This happens when skaffold.NewForConfig fails when skaffold fails to create

• a builder,
• deployer,
• init build dependencies
• init sync
• init watch trigger

Any errors occurred here will now be part of "INIT" phase.

This PR also identifies failure when deploy context is minikube and minikube cluster is stopped.
On master run

1. minikube stop
2. kubectl config use-context minikube
3. skaffold dev

Error,

 skaffold dev     
creating runner: creating builder: getting docker client: getting minikube env: running [/Users/tejaldesai/Downloads/google-cloud-sdk2/bin/minikube docker-env --shell none -p minikube]
 - stdout: "* The control plane node must be running for this command\n  - To fix this, run: \"minikube start\"\n"
 - stderr: ""
 - cause: exit status 89
➜  microservices git:(minikube_errr) ✗ 

With this PR

 ../../out/skaffold dev
minikube is probably not running. Try running "minikube start".

Make sure the error is seen in Event API
Since this happens pretty fast, In another terminal run

 watch --interval=0.1 curl localhost:50052/v1/events >> test.txt

in test.txt

{"result":{"timestamp":"2020-10-19T22:15:10.426813Z","event":{"metaEvent":{"entry":"Starting Skaffold: \u0026{Version:v1.15.0-23-gec73dafff ConfigVersi^[[10;1Hon:skaffold/v2beta9 GitVersion: GitCommit:ec73dafff8fd5714fabea148270d975de05b5449 GitTreeState:clean BuildDate:2020-10-19T14:58:30Z GoVersion:go1.14.3^[[11;2HCompiler:gc Platform:darwin/amd64}","metadata":{"build":{"numberOfArtifacts":2,"builders":[{"type":"DOCKER","count":2}],"type":"LOCAL"},"deploy":{"dep^[[12;1Hloyers":[{"type":"KUBECTL","count":1}],"cluster":"MINIKUBE"}}}}}}^M^[[13d{"result":{"timestamp":"2020-10-19T22:15:10.528741Z",

"event":{"sessionEndEvent":{
   "status":"Failed",
    "err":  {
                 "errCode":"INIT_MINIKUBE_NOT_RUNNING_ERROR",
                 "message":"creating builder: getting docker client: getting minikube env: running [/Users/tejaldesai/Downloads/google-cloud-sdk2/bin/minikube docker-env^[[15;2H--shell none -p minikube]\n - stdout: \"* The control plane node must be running for this command\\n  - To fix this, run: \\\"minikube start\\\"\\n\"\^[[16;1Hn - stderr: \"\"\n - cause: exit status 89",
   "suggestions":[
        {"suggestionCode":"START_MINIKUBE","
          action":"Try running \"minikube start\""}
   ]}}

[codecov]

Codecov Report

Merging #4926 into master will increase coverage by 0.17%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #4926      +/-   ##
==========================================
+ Coverage   72.18%   72.36%   +0.17%     
==========================================
  Files         358      360       +2     
  Lines       12402    12474      +72     
==========================================
+ Hits         8953     9027      +74     
+ Misses       2795     2789       -6     
- Partials      654      658       +4     

Impacted Files	Coverage Δ
pkg/skaffold/errors/build_problems.go	100.00% <ø> (ø)
cmd/skaffold/app/cmd/runner.go	71.05% <100.00%> (+0.78%)	⬆️
pkg/skaffold/errors/err_map.go	96.66% <100.00%> (ø)
pkg/skaffold/errors/errors.go	96.77% <100.00%> (+16.77%)	⬆️
pkg/skaffold/errors/init_problems.go	100.00% <100.00%> (ø)
pkg/skaffold/event/event.go	91.76% <100.00%> (+0.65%)	⬆️
pkg/skaffold/runner/new.go	64.28% <100.00%> (+0.23%)	⬆️
pkg/skaffold/schema/v2beta8/upgrade.go	88.88% <0.00%> (-11.12%)	⬇️
pkg/skaffold/build/cache/cache.go	53.65% <0.00%> (ø)
pkg/skaffold/deploy/util/logfile.go	80.00% <0.00%> (ø)
... and 11 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 5d8b798...22174fa. Read the comment docs.

[gsquared94]

LGTM, other than logEntry arriving out of order seems like a pre-existing issue.

[briandealwis]

A few suggested renames, mostly to avoid confusion with skaffold init, and minor nits.

[briandealwis]

One nit