[Desktop][Feat] Allow to change stress score by hand

[kyukhin]

Is your feature request related to a problem? Please describe.
I am not a good swimmer and many of my pieces of training in the pool contain exercises. So, my Garmin usually calculates distances much longer than it actually is. I wouldn't care about it at all, but it affects trends calculated by Elevate much.

For example, today my distance calculated by Garmin was 3.800, while I swam 2.900 which will make the trend lie about my fatigue.

Describe the solution you'd like
There's a well-known abb called TP which makes it possible to change stress score by hand. Why not add something similar to Elevate? So, that I will be able to set today's training SS to say 50 and make trends true.

Describe alternatives you've considered
I was thinking of asking Strava to let update the swimming distance, but I doubt they will do that.

Additional context
This looks like a common problem for newbies, I've asked around.