Implement 1RM calculator

[senier]

Prototype for 1RM calculator. Please let me know what you think.

[treiher]

That's a nice extension. Here are some thoughts:

On the training session page:

• A modal overlay could be a bit nicer as the currently used dropdown, because all other information on the page would be faded out. It also centers the information on the screen, so that no scrolling is needed.
• Just going down to 50% 1RM could be enough. Who wants to do more than 30 reps?
• It could be useful to have 5% steps.
• The info button could be hidden if there is no information to show.
• It could be useful to also have a 1RM calculator where a custom value could be entered. We could add a button for that to the navigation bar, as it is done for the Stopwatch/Metronome/Timer overlay. An alternative could be adding it to the hamburger menu, so that the calculator could be used on every page.

On the exercise page:

• The 1RM chart: The current implementation leads to steps and gaps in the average graph (see example below). A "value-based" centered moving average (instead of the currently used interval-based one) would lead to nicer charts. I also don't see the advantage of using a fixed interval for the average here. Just using a simple average like in the weight chart would be most consistent with the other charts on the exercise page.

• The fact that the 1RM table has a title is inconsistent. Other parts of the page don't have titles.
• The meaning of the date above the 1RM table is unclear.
• Maybe it would be better to remove the 1RM table and just add a "Avg. 1RM" column to the training session table. The X% 1RM values are not interesting to me here.