Verify Clojure-LSP download using a checksum

[mrkam2]

When downloading nightly (and other builds) of clojure-lsp verify the download with a checksum. See the discussion in https://clojurians.slack.com/archives/CBE668G4R/p1717093602176859?thread_ts=1717011164.563769&cid=CBE668G4R. And corresponding LSP issue to produce the checksums in clojure-lsp/clojure-lsp#1828.

[PEZ]

Even if clojure-lsp does not add this, we can get far if we actually re-download when the user tries to do that.