Support additional commit operations in the Web IDE

MR: Pending

Description

As a Web IDE user, I want to be able to amend a commit and force push changes to avoid context switching between the Web IDE and other source control tools to perform these operations.

Acceptance criteria

• Add an option to Amend commit & force push to the source control panel's dropdown menu and the commit button in the Web IDE.
• Add an option to Commit & force push to the source control panel's dropdown menu and the commit button in the Web IDE.

Design notes

You can take a look at VSCode Desktop's source control panel for guidance on where to places these menu options

Commit button	Source control dropdown menu

Implementation plan

• Follow the VSCode's source control provider documentation to learn how to add additional source control features to VSCode: https://code.visualstudio.com/api/extension-guides/scm-provider
• Use the Commit REST API's force attribute to overwrite commits in a branch: https://docs.gitlab.com/api/commits/#create-a-commit-with-multiple-files-and-actions
• Web IDE's source control implementation https://gitlab.com/gitlab-org/gitlab-web-ide/-/tree/main/packages/vscode-extension-web-ide/src/scm?ref_type=heads