TRE install friction: INSTALL.md and acro_init() tell different stories

[shamykyzer]

This came out of PR #49, related to automate updating changelog from PR names for ACRO-R, a bigger mismatch that failed macos-ci check constantly: the install guide tells the user to set up a Python environment by hand and install acro into it, but the R code in acro_init() also tries to do this automatically, the two paths do not check each other, so if a user already has acro available somewhere the code does not notice and still tries to install it from scratch, on a TRE that cannot reach PyPI this fresh install fails and the user is stuck, happy to be corrected if I am missing something

A few ideas worth gut checking me on,

• before building a new environment, could install_venv first check whether acro is already importable from a few likely Python interpreters, if any of them already has acro then use that one and skip the install, this would let users who already have acro installed by an admin avoid the broken install path

• could the install guide be split into two clear routes, one for desktop users who can let acro_init() handle everything, and one for TRE users where an admin has to install acro ahead of time, right now the guide mixes both paths and that is confusing

• could the conda install option from feat: add support for conda environments #35 and the admin workaround from [Documentation] Add more help for reticulation setup problems #20 be written up as named recipes in the install guide, that would also close out [Feature] Gather more feedback to document support for conda-forge environments #29 which has been open since November

[shamykyzer]

• inst/INSTALL.md also has a handful of small typos and broken examples that trip up copy paste on a TRE where users cannot easily search the web for fixes, the ones I have spotted:
  • line 36, conda create --n r-acro, the flag should be -n or --name, --n is not valid
  • line 53, conda deactivate r-acro, conda deactivate does not take an argument
  • line 56, **On Windows**from the command line, missing space between the bold close and from
  • line 70, the heading reads **On linux/mac** using conda: but the block below runs source r-acro/bin/activate then python -m pip install acro, that is venv plus pip, not conda
  • line 84, the R `front-end', mismatched backtick and apostrophe, also the sentence is unterminated
  • line 93, install.packages*("reticulate"), stray asterisk before the parenthesis
  • line 119, you add add one of the following lines, duplicated add
  • line 129, library("acro)", the closing quote is inside the parenthesis, should be library("acro")
  • lines 136 to 137, Sys.getenv("USERPROFILE") is Windows only, on linux and mac the equivalent variable is HOME, the example will silently produce an empty path on those systems
  • line 143, [site-wide Rprofile]() has an empty link target, and using replacing *~/r-acro* has a duplicated verb

for reference, the functions in R/acro_init.R, get_python() at line 9, install_conda() at line 24, install_venv() at line 34, and acro_init() at line 76