Changes in vcpkg/build_iroha_deps.sh file and documentation to inform users that Iroha 1 is working in Raspberry Pi 4 (from HL main repo)

[baziorek]

Full description from #2944. Because of security reason those changes must be done from main hyperledger repository, not forks.

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Description of the Change

History

Lets start with what is not really important - history:
Few years ago I managed to build Iroha 1.1.3 on RPI3 and RPI4, I created special tutorial:
https://wiki.hyperledger.org/pages/viewpage.action?pageId=41584046
After that I was suggested to create PR (#728) and @lebdron created his PR (#864) to make building on RPI as automatic as possible.
During those few years I was thinking that I should create similar PR for develop version, but it was really hard (as You see PR from @lebdron). Recently somebody from community posted message that he is using Iroha 1.5 on RPI: https://t.me/hyperledgeriroha/25004 - it added me motivation to try again...

Important description of change

1. vcpkg/build_iroha_deps.sh - to use vcpkg on RPI ( aarch64 architecture ) we need export VCPKG_FORCE_SYSTEM_BINARIES=1 before calling vcpkg.
2. Added information to documentation to expose that Iroha 1 can be build on RPI and build process is easy.
3. I noticed problem with building documentation (instruction: https://github.com/hyperledger/iroha/tree/main/docs):

make html
...
Could not import extension m2r2 (exception: No module named 'm2r2')

that is why I added entry to docs/source/requirements.txt file

Issue

Benefits

If somebody wants to build Iroha for RPI4 - it would be easier for users. Also if somebody (who does not know Iroha) would like to find blockchain who is working on RPI - it will be easier.

Possible Drawbacks

Review process:D.

Usage Examples or Tests [optional]

Testing on RPI4 according to https://iroha.readthedocs.io/en/develop/build/index.html#linux-pre:

apt-get update; \
apt-get -y --no-install-recommends install \
   build-essential ninja-build \
   git ca-certificates tar curl unzip cmake \
   pkg-config zip

git clone -b rpi_fix https://github.com/baziorek/iroha.git
cd iroha
./vcpkg/build_iroha_deps.sh $PWD/vcpkg-build

cmake -B build -DCMAKE_TOOLCHAIN_FILE=$PWD/vcpkg-build/scripts/buildsystems/vcpkg.cmake . -DCMAKE_BUILD_TYPE=RELEASE -DUSE_BURROW=OFF -DUSE_URSA=OFF -DTESTING=OFF -DPACKAGE_DEB=OFF

cmake --build ./build --target all

./build/bin/irohad
# log from irohad with missing arguments was printed

Alternate Designs [optional]

Different description