Remove outdated docker section from INSTALL.md

[SECtim]

The fstarlang docker images have not been updated for years and thus should not be referenced in the installation instructions.

The corresponding wiki page should probably also be updated with a corresponding note at the top (or removed altogether, but I am unsure of the F* team's wiki policy about outdated content).

[SECtim]

See also #2788 and #3183.

[nikswamy]

@tahina-pro : I'm guessing that you would know the most about this? What's up with our docker images? Do we plan to maintani them or should we just remove them from the docs as suggested here?