Rework (potentially remove) "Account" page on the User Dashboard. Add login / logout buttons for GitHub / GitLab / BitBucket
Is your task related to a problem? Please describe

Currently, the account page is outdated and fetches the user information from db that is planned to be removed as part of https://github.com/eclipse/che/issues/21374
The data provided on the Account page is irrelevant and should be removed
Describe the solution you'd like
As part of this issue, we should only have the login / logout buttons to the main Git providers GitHub, Gitlab, and Bitbucketlogin/logout
Describe alternatives you've considered
Potentially we should remove Account page completely and add Git Services Tab to the User Preferences:

Additional context
The information about the configuration of the particular Git provider should be fetched from the Eclipse Che CR - https://github.com/eclipse/che/issues/21577
The issue is part of the Git Zero Config epic - https://github.com/eclipse/che/issues/20583
Open Questions:
- login / logout URLs should be provided by the Che CR
- how should we track the login / logout state for a particular user