containers as functions (#1681)

PR adds a new executortype which supports running containers as functions. New CLI under functions is added to create container as functions.

Co-authored-by: Harsh Thakur <harshthakur9030@gmail.com>
Co-authored-by: Sanket Sudake <sanketsudake@gmail.com>

.golangci.yaml

@@ -1,22 +1,38 @@
 linters:
   enable:
+    # Default linter
     - deadcode
-    - gofmt
-    - goimports
+    - errcheck
     - gosimple
     - govet
     - ineffassign
-    - misspell
-    - nakedret
     - staticcheck
     - structcheck
     - typecheck
-    - unconvert
+    - unused
     - varcheck
+    # Additional linters
+    - gofmt
+    - goimports
+    - misspell
+    - nakedret
+    - unconvert
+    # Enable in future
+    # - bodyclose
+    # - dogsled
+    # - dupl
+    # - gosec
+    # - ifshort
+    # - nilerr
+    # - prealloc
+    # - revive
+    # - unparam
+    # - wrapcheck
+    # - gocritic
 linters-settings:
   errcheck:
     ignore: go.uber.org/zap:Sync
   goimports:
     # put imports beginning with prefix after 3rd-party packages;
     # it's a comma-separated list of prefixes
-    local-prefixes: github.com/fission/fission
+    local-prefixes: github.com/fission/fission