Upgrade Flask to current

[mfeit-internet2]

Cannot upgrade until we drop OL8, which is at 3.6. Werkzeug requires 3.8.

We've been building and using Flask 1.1.1 for quite some time. Current is 2.0.3.

• Determine if the current version will work (or make it work)
• Check what Debian is using.
• Deal with dependencies we may no longer need (python-itsdangerous, python-werkzeug)

Distro	Flask	Itsdangerous	Werkzeug
ol8	0.12.2	0.24	0.12.2
el9	2.0.3	2.0.1	2.0.3
d11	1.1.2	1.1.0	1.0.1
d12	2.2.2	2.1.2	2.2.2
u20	1.1.1	1.1.0	0.16.1
u22	2.0.1	2.1.0	2.0.2
u24	3.0.2
Current	3.0.3	2.2.0	3.0.3