[INFRA] Enable header tests for search module

[eseiler]

Blocked by xxsds/sdsl-lite#66

Now that the SDSL passes the header tests, we can re-enable the header tests for the search module.

[marehr]

It seemes that gcc-7 still has linkage problems:

CMakeFiles/seqan3_header_test--seqan3-search-algorithm-all-2.dir/seqan3_header_test_files/seqan3/search/algorithm/all-2.cpp.o: In function `sdsl::sorted_stack_support::operator==(sdsl::sorted_stack_support const&) const':
all-2.cpp:(.text+0x10): multiple definition of `sdsl::sorted_stack_support::operator==(sdsl::sorted_stack_support const&) const'
CMakeFiles/seqan3_header_test--seqan3-search-algorithm-all-1.dir/seqan3_header_test_files/seqan3/search/algorithm/all-1.cpp.o:all-1.cpp:(.text+0x10): first defined here
CMakeFiles/seqan3_header_test--seqan3-search-algorithm-all-2.dir/seqan3_header_test_files/seqan3/search/algorithm/all-2.cpp.o: In function `sdsl::sorted_stack_support::operator!=(sdsl::sorted_stack_support const&) const':
all-2.cpp:(.text+0xb0): multiple definition of `sdsl::sorted_stack_support::operator!=(sdsl::sorted_stack_support const&) const'
CMakeFiles/seqan3_header_test--seqan3-search-algorithm-all-1.dir/seqan3_header_test_files/seqan3/search/algorithm/all-1.cpp.o:all-1.cpp:(.text+0xb0): first defined here
CMakeFiles/seqan3_header_test--seqan3-search-algorithm-search-1.dir/seqan3_header_test_files/seqan3/search/algorithm/search-1.cpp.o: In function `sdsl::sorted_stack_support::operator==(sdsl::sorted_stack_support const&) const':
search-1.cpp:(.text+0x10): multiple definition of `sdsl::sorted_stack_support::operator==(sdsl::sorted_stack_support const&) const'

[eseiler]

Yes, it's blocked by an sdsl PR. I introduced some not-inline functions when I pushed the cereal support.
The PR fixes this (and introduces a header test).

[codecov]

Codecov Report

Merging #933 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #933   +/-   ##
=======================================
  Coverage   96.41%   96.41%           
=======================================
  Files         181      181           
  Lines        6640     6640           
=======================================
  Hits         6402     6402           
  Misses        238      238

Impacted Files	Coverage Δ
.../search/algorithm/configuration/max_error_rate.hpp	90% <ø> (ø)	⬆️

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[eseiler]

@smehringer I fixed the upstream problems, so this is now ready for review