Revert ".gitlab-ci.yml: move coverage analysis to the end, set it manual"

Reverts commit c0d14efb.
We don't need this extreme solution: coverage can be quick if not computing
branch coverage.
9 jobs for feature-a/3187-dont-filter-with-few-kmers in 40 minutes and 2 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test Tools
passed #130554
test_tools

00:00:03

 
  Test Unit
passed #130555
test_algo_unit

00:03:29

passed #130556
test_tools_unit

00:00:03

 
  Test Functional
passed #130557
test_algo_should

00:13:17

 
  Test Shouldvdj
passed #130558
test_algo_shouldvdj

00:11:07

 
  Coverage
passed #130559
algo_coverage

00:00:05

87.0%
 
  Prepare Release
manual #130560
allowed to fail manual
prepare_release
 
  Valgrind Unit
passed #130561
valgrind
algo_valgrind_unit

00:11:56

 
  Valgrind Functional
manual #130562
valgrind allowed to fail manual
algo_valgrind_functional