* Adds custom comparison for checking multiple substrings
This changeset introduces custom comparison for checking if a target
string has given multiple substrings, namely `ContainsMultipleSubstrings`.
Also removes `commands.TestContains` function and replaces all references
of `commands.TestContains` with `gotest.tools/assert.Check` function and
uses `ContainsMultipleSubstrings` as comparison function.
* Renames and makes the compare function variadic
New name: ContainsAll
New location: pkg/util/compare.go
Also the function now takes target string as first arg,
and accepts any number of substrings to check.
Removed the message arg, the compare function composes the error message.
For eg:
```
Actual output: foo-abcd foo <unknown> 0 OK / 0 <unknown> <unknown>
Missing strings: foo-abcd1, foo1
```
* Adds tests for compare utility ContainsAll
* Update vendor/modules.txt
* Adds kn revision delete command
* Adds unit tests for revision delete command
* Adds integration tests for revision delete command
Added revision delete command tests in new workflow namely
TestRevisionWorkflow.
* Removes extra line and renames an import alias
* Adds 10 seconds sleep between service create and revision delete
Also adds check for 'No resources found' while grabbing revision name.
* Clean up imports
* Removes the pause after service create
* Updates testing output strings in unit and e2e
* Updates post goimports on hack and test dirs
Navid Shaikh