Patches for elpa-admin

[Philip Kaludercic]

Hi,

I attach two patches for elpa-admin:

The somewhat recent addition to render markdown caused an error when
building a package locally on my system, as the executable "markdown"
was not installed.  So I gathered a number of implementations and
had had `elpaa--section-to-html' use whatever is installed:

0001-Avoid-failure-if-no-markdown-compiler-is-installed.patch
Description: Text Data

As an alternative to bubblewrap, GNU Guix can also be used for
sandboxing.  It doesn't take much to get it to work and after the
package profile has been prepared it is just as quick as bwrap:

0002-Support-sandboxing-using-Guix.patch
Description: Text Data

This approach could also be extended to Nix/nix-shell, but I have no
experience with that tool.  This might be of interest to anyone using a
Macintosh system and interested in isolation, as AFAIK Nix works on
those.

(On a related note, is it necessary to sandbox markdown rendering?  I
understand why org can be dangerous, but markdown shouldn't be able to
have any side effects?)

If these changes are fine, I can push them myself.

-- 
        Philip Kaludercic