Update README.md of Reva repo

[prashant-gurung899]

https://github.com/opencloud-eu/reva/blob/main/README.md

Some of the links in the Readme file leads to a broken link give "Page Not Found" response.
Example:

reva.webm

Also, commands under RUN need to be updated > path examples/storage-references doesn't exist in the repo

[individual-it]

links corrected:

• delete wrong references to the docs reva#331
• fix references to drone reva#332
• update obsolete branch name and delete version schema reva#333