[FEATURE] Reduce memory footprint of FM-indices over text collections

[eseiler]

Changes

Using sdsl::sd_vector_builder

The builder can be used iff

• You know the bitvector size
• You know the number of 1s you want to set
• The positions of the 1s are in a strictly increasing order

Since we actually fulfil all these requirements, we can use the builder.
This already reduces the memory footprint by a little bit - you do not need to allocate a bitvector of size text_size ( a vector using text_size/8 many bytes).
This may be more noticeable for bigger texts since the allocation will take longer. Since I only measured memory peak, it's hard to tell exactly (the other steps use way more memory).

Avoiding a copy

We can get rid of the copy from std::vector<uint8_t> to sdsl::int_vector<8>.
Note that we need to do a std::ranges::reverse(tmp_text); afterwards.
The alternative would be to do a views::deep{views::reverse} followed by an views::reverse in the std::ranges::move, but the deep reverse is very expensive (run time wise), so it's actually better to reverse the vector after flattening (views::join) it.
Also: We cannot do the views::reverse after the views::join because views::join strips the bidirectional(?) property off the range and hence views::reverse won't work.

I did some local benchmarks with a text of size 256Mbp.
The times are around the same, with this new version tending to be a bit faster.
Memory peak was reduced from 3,213,168 KB to 2,885,388 KB (- 10%).
Considering the text is only 256MB, the memory consumption is still rather high, though.

Todos

• Add std::ranges::reverse to std/algorithm and use it instead of std::reverse

[codecov]

Codecov Report

Merging #1363 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master    #1363   +/-   ##
=======================================
  Coverage   97.49%   97.49%           
=======================================
  Files         218      218           
  Lines        8703     8703           
=======================================
  Hits         8485     8485           
  Misses        218      218

Impacted Files	Coverage Δ
include/seqan3/search/fm_index/fm_index.hpp	100% <100%> (ø)	⬆️

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[rrahn]

lgtm