Update flask to a more recent version

[rkoumis]

update what dependencies we can, without too much churn. For example:

    "Flask==3.0.3",
    "redis==5.2.0",
    # there is newer ruamel available but dalton.py changes would be needed
    "ruamel.yaml<0.18.0",
    "idstools==0.6.5",
    "flowsynth>=1.4.1",

• Remove Flask-Script and Flask-Assets, they don't seem to be used
• Remove Flask-Caching and Flask-Compress, they are not useful

[rkoumis]

See #221 for this work

[rkoumis]

Closing with #222