doc/README.md: Improve the Hugo Quick start guide for an easier start

[bernhardkaindl]

Hi @robhoes!

this PR tweaks the Quick start guide in doc/README.md to give some bits of information that I were helping me at getting started to add a new page to the new Hugo-based docs, because I had never used Hugo before.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Additional details and impacted files

@@           Coverage Diff            @@
##           master   #5699     +/-   ##
========================================
- Coverage    51.4%   44.8%   -6.6%     
========================================
  Files          13      16      +3     
  Lines        1928    2210    +282     
========================================
+ Hits          991     992      +1     
- Misses        937    1218    +281     

see 4 files with indirect coverage changes

Flag	Coverage Δ
python2.7	45.5% <ø> (?)
python3.11	51.4% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

[bernhardkaindl]

The ocaml action failed with these messages (same on the feature/py3 branch these days once) temporarily:

https://github.com/xapi-project/xen-api/actions/runs/9561378415/job/26355461589

 File "ocaml/xenopsd/test/dune", line 2, characters 7-11:
2 |  (name test)
           ^^^^
(cd _build/default/ocaml/xenopsd/test && ./test.exe)
{xenops test}
(cd _build/default/ocaml/tests && ./test_vdi_cbt.exe)
{Test Events and VDI CBT }
(cd _build/default/ocaml/tests && ./suite_alcotest.exe)
{Base suite}
(cd _build/default/ocaml/xapi-idl/lib_test && ./test.exe)
{Base suite}
File "ocaml/xenopsd/test/dune", line 2, characters 7-11:
2 |  (name test)
           ^^^^

The xenops test also shows this error when expanding the log group:

 [20240618T08:22:13.740Z|debug||20 |test|xenops_server] begin_Parallel:task=152.atoms=0.(VBD.plug RW vm=105)
  
              Raised at Xenops_interface.err.(fun) in file "ocaml/xapi-idl/xen/xenops_interface.ml", line 119, characters 8-17
              Called from Idl.Exn.GenClient.declare_.inner in file "src/lib/idl.ml", line 558, characters 28-46
              Called from Dune__exe__Test.task_ended in file "ocaml/xenopsd/test/test.ml", line 54, characters 8-33
              Called from Dune__exe__Test.wait_for_tasks.(fun) in file "ocaml/xenopsd/test/test.ml", line 94, characters 15-33
              Called from Stdlib__List.iter in file "list.ml", line 110, characters 12-15
              Called from Dune__exe__Test.wait_for_tasks in file "ocaml/xenopsd/test/test.ml", line 91, characters 4-184
              Called from Dune__exe__Test.vm_test_parallel_start_shutdown in file "ocaml/xenopsd/test/test.ml", line 518, characters 2-22
              Called from Alcotest_engine__Core.Make.protect_test.(fun) in file "src/alcotest-engine/core.ml", line 181, characters 17-23
              Called from Alcotest_engine__Monad.Identity.catch in file "src/alcotest-engine/monad.ml", line 24, characters 31-35
              
  Logs saved to `~/work/xen-api/xen-api/_build/default/ocaml/xenopsd/test/_build/_tests/xenops test/xenops test.010.output'.
   ──────────────────────────────────────────────────────────────────────────────
  
  Full test results in `~/work/xen-api/xen-api/_build/default/ocaml/xenopsd/test/_build/_tests/xenops test'.
  1 failure! in 4.093s. 125 tests run.

Re-running the Ocaml tests now.

[psafont]

I need to take a look at that failure