Allow Che 7 Git + SSH Flow

The problem

As mentioned in #12850 git+ssh is currently not working (cloning a project). A user is able to generate an SSH key pair with the ssh plugin (even if currently this plugin doesn’t seems to be included in che-theia) but:

• cloning may happen at IDE startup (a user won’t be able to generate the keys)
• git in che-theia doesn’t support SSH
• ssh keys are only available in che-theia container

The proposed flow

Here is a list of steps/task of a git+ssh flow that I have splitted in 3 priority levels:

🦄critical for the GA: allow SSH key persistence and usage 🐴nice to have for the GA: automate for a better UX and get rid of the SSH plugin 🐮postponed after the GA: leverage GitHub token when available to automate even more

First time user login

• 🐴Generate SSH keys when the user login for the first time and store them in user preferences #14411
• 🐮If a GitHub token is available upload the SSH key to GitHub

At workspace creation:

• 🦄mount the SSH keys as secrets in all workspace containers #13520
• 🐴setup (or mount?) git config (name and email) #13874

At workspace cloning with git+ssh:

• 🐴Check if the user can authenticate
• 🐴If the user cannot be auth but it’s a GitHub URL
  • 🐮If we have his GitHub token: automatically upload the SSH key
  • 🐴If we don’t have his GH token prompt him to upload the key manually
• 🐴If the user cannot be authenticated and it’s not GitHub prompt the user to do the following steps after the workspace is started 1) generate the key using the addon if that hasn’t been done yet 2) add its SSH public key to the git server 3) clone the project or restart the workspace

Misc

• 🦄Add git+ssh support in che-theia container #12850
• 🦄Enable the SSH plugin
• 🐴Make sure that current Che 7 stacks have git+ssh support
• 🐴Add git+ssh scenario in e2e happy path tests

[vitaliy-guliy]

The UX when cloning of Git repositories with SSH uri was improved and merged.

[l0rd]

We have discussed that the current behavior of the SSH plugin should be changed.

1. There should be 2 generate commands: SSH: generate key pair... and SSH: generate key pair for particular host...
2. SSH: generate key pair for particular host... works as the currently implemented in https://github.com/eclipse/che-theia/pull/352/files
3. SSH: generate key pair... instead would add a key for the generic host

Host *
  IdentityFile <path>

1. SSH: generate key pair... would send a request the the SSH manager with parameters { "service" : "vcs", "name": "default-<timestamp>"}
2. When a user call SSH: generate key pair... a second time a new key will be generated and added, the previous keys won’t be deleted.