[Taler] (docs) installation

[Thien-Thi Nguyen]

In "Installation of dependencies" (§3.3.1 in the GNU Taler
Merchant Backend Operator Manual), i have one question:

(a) What is the minimum required version for Taler Exchange?

and several proposals:

(b) I'd like to stop documenting "build from Git".  This would
    reduce the number of dependencies (autotools and ilk),
    simplify many instructions, and reduce the support burden.
    (This is in line w/ our goal of making the docs for the
    integration process "obvious, easy, accessible", i think.)

(c) I'd like to link to <http://ftpmirror.gnu.org/gnunet/>
    and <http://ftpmirror.gnu.org/taler/> to emphasize released
    packages.

(d) I'd like to link to the info-gnu mailing list when talking
    about "release announcement".  That seems to be the general
    place, but if there is a better one, please let me know.

BTW, i'm sending this message w/o signing it because during the
process of trying to upgrade my (10yo) computer to be able to
install GNUnet and Taler, i have somehow lost the ability to
sign messages from w/in Emacs (was 26.1, now 27.1), and have not
yet resolved the issue.  (This is partly why i want to stop
documenting "build from Git" -- less is more in this case!)

-- 
Thien-Thi Nguyen -----------------------------------------------
 (defun responsep (query)               ; (2020) Software Libero
   (pcase (context query)               ;       = Dissenso Etico
     (`(technical ,ml) (correctp ml))
     ...))                              748E A0E8 1CB8 A748 9BFA
--------------------------------------- 6CE4 6703 2224 4C80 7502