docs: import meta-ts docs

Rather than constantly linking our docs to meta-ts, import the documentation directly into our tree and switch all the external links to internal ones.

Note that there are still some links pointing to older ledge-rp images, because we don't have a stable snapshots directory yet. Those will be fixed once the gitlab build stabilizes

Signed-off-by: Ilias Apalodimas ilias.apalodimas@linaro.org