Config, install, readme & realization updates

[madMatchstick]

Minor non-code updates

Changes

1. config.txt(s): all instances of sft_coupled to is_sft_coupled per cfe pr #105
2. INSTALL.md:
   1. add -DNGEN_IS_MAIN_PROJECT=ON flag to the noah-owp-modular lib build
   2. Remove sft submodule update from LASAM build (not officially listed in ngen/extern)
   3. Some markdown syntax changes for better c/p
3. example/README.md: dir test already exists, suggest ngen/test_sft
4. realizations/realization_standalone.json: update sft lib path

Todos

1. Need to revisit the instructions for "Example 3: Integrated models (SLoTH+SMP+SFT+CFE/LASAM) example with NOAH-OWP-Mod". Perhaps some pathing and/or symbolic linkage is off?
2. Couple general questions regarding install,
   1. Why are we updating some submodules but not others?
   2. Why ngen build to include PYTHON and SQLITE for this particular workflow(s)?

[ajkhattak]

This looks good to me. Thanks for the updates...