Add ability to create application resource/template from stack

[johnmcollier]

User Story

As a user, I want to be able to use odo to point to a devfile/stack that has its own application template associated with it, and have the template generated on my disk. This will be similar to the appsody init command that we're trying to replicate in odo.

Acceptance Criteria

• It should clone/download project/application resources on my disk from a template associated with a stack/devfile
  • If sparseCheckoutDir is set, need to pull down the specified folder from the git repo, rather than the entire repo
• resource creation will only be triggered when:

1. experimental flag has been enabled

2. the component is a devfile component

3. there is a project defined in the devfile of the given component

4. odo component create command called with a --downloadSource flag

• if a devfile contains a command called devInit, the devInit command will be executed at the end of the odo component create to do any init setup that the stack needs
• the devInit command should function similarly (if not equivalently) to the appsody init command

Links

• Parent epic: MVP: Local support for devfile push #2576

CC @neeraj-laad

/kind user-story
/area devfile

[elsony]

Added more details on the requirement on the description

[elsony]

Based on the Sprint plan discussion, we need to figure out a better name than --createResource to clarify that the creation/cloning of resource is on the local file system instead of creating Kube resources.

[EnriqueL8]

@upLukeWeston and I added some notes on this issue here
FYI: @johnmcollier @elsony

[GeekArthur]

FYI, this issue #2850 description includes the rough design for template support, we can discuss and finalize the design later then just use one issue for tracking purpose.

[elsony]

This item is done with the remaining issues have separate items opened