Vscode-extension-for-zowe: Update Top level Readme Tip with link to docs/Readme-Theia.md

[zFernand0]

Is it possible to add a link on the top level readme file that directs people to https://github.com/zowe/vscode-extension-for-zowe/blob/master/docs/README-Theia.md

It could be as simple as updating the Tip on the first section of the Readme. : )

_Originally posted by @zFernand0 in https://github.com/zowe/vscode-extension-for-zowe/issues/343#issuecomment-564044815_

[IgorCATech]

Absolutely, Fernando! Let me see...
Do you want to update it right now, or can it wait till the 1.1 Release?

[zFernand0]

Feel free to open the PR whenever you get a chance :)
Thanks a lot!