Additional dynamic elements needed

[tyoung-99]

Running list of additional necessary dynamic elements noticed during other work. Depending on how much info ends up on the Features/Traits or Buffs pages, maybe add a shown/hidden flag to only display what's really necessary.

• [x] Add buffs page for general buffs/debuffs, add flag to note buff vs debuff
• [x] Max HP - base chosen by user + CON + other buffs
• [x] Current HP - base is static number, to be set to max minus buffs to current on long rest (#10) + other buffs (this is already implemented as much as it can be here, just noting b/c of the future implementation necessary)
• [x] Ability scores - base chosen by user + other buffs (including ASIs)
• [x] Saving throw profs - base from 1st class + other buffs
• [x] Other profs - class + race + background + other buffs (can't be totally dynamic, as no calculation is done, just implement class/race/background identifiers for future use)
• [x] Speeds - base from race + other buffs
• [x] Skills - base from class/race/background chosen by user + other buffs
• [x] Passive perception - base from perception mod + other buffs

[tyoung-99]

This won't actually be closed after the PR is merged, since it'll stay as a running list, so I'll reopen it at that point.