https://gitlab.com/gitlab-org/gitlab-ce/issues/60932

**Why?**
These values will be used to help build the mirroring diff.
It is helpful keeping it controlled in a constant.

**Links:**
- https://gitlab.com/gitlab-org/gitlab-ee/issues/10232
- https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/11478

This reverts commit 2869a61f3b7aeb8b6d79c74332c93e32cec20caa.

- When uploading a file, we need to flag binary files correspondingly
so that it gets propagated all the way to RepoEditor as it decides on
whether to show editor for this or that file or not (shouldHideEditor())

- rawPath needs to be propagate all the way to ContentViewer as well so
that uploaded images could be rendered as a base64 image right away
instead of raw base64 string

Resolve "Shortcut to create merge request from Web IDE"

Closes #57482

See merge request gitlab-org/gitlab-ce!26792

Resolve "Support creating new file from URL in the Web IDE"

Closes #57668

See merge request gitlab-org/gitlab-ce!26622

Fix IDE file dropdown

Closes #60021

See merge request gitlab-org/gitlab-ce!27015

**Why?**
Currently the IDE loads a merge request based on only the
`source_branch` name. This means it loads MR's from
forks that have the same branch name (not good).

- This required updating the BE API to accept `source_project_id`

**Why?**

Previously it managed this as an internal data property, but there
was extra complexity involved because the component doesn't have
all the information it needs (i.e. the `mouseOver` prop).

This is a good opportunity to colocate the data prop with the component
that has the information to change it (i.e. `file_row`) and let
`new_dropdown/index` receive this value as a prop.

Before the user had to choose between committing to a new branch,
committing to a new branch AND creating an MR, or committing to the
current branch regardless of whether or not it already has an MR.

This commit separates the creation of an MR from whether or not they
commit to an existing or new branch