relicense all paths other than MIT licensed code, client/cody*, jetbrains, VS code, and browser extension to enterprise (#53345) (#53345)

Preparing for 5.1 based on latest executive decisions. Re-licensing the
majority of sourcegraph/sourcegraph to enterprise instead of Apache.
Official external statements forthcoming with 5.1 release.

[Searching this branch for LICENSE files
](https://sourcegraph.sourcegraph.com/search?q=context:sourcegraph+repo:%5Egithub%5C.com/sourcegraph/sourcegraph%24+file:LICENSE%24+-file:client/cody+rev:cclark/relicense&patternType=standard&sm=1&groupBy=path)

This leaves only 2 licenses in directories other than `client/cody*`
1. MIT code in syntax highlighter
2. MIT code in react-accessible-treeview

Edit: updates from exec team
Jetbrains extension / VS Code extension / browser extension will remain
Apache

Here is a search showing all Apache licensed paths in this branch
https://sourcegraph.sourcegraph.com/search?q=context:sourcegraph+repo:%5Egithub%5C.com/sourcegraph/sourcegraph%24+file:LICENSE%24++rev:cclark/relicense&patternType=standard&sm=1&groupBy=path

If either of those should be changing, please let me know.
## Test plan
N/A
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