Add locale for fi-FI

[lauft]

The following locale needs to be verified/completed:

class fi_FI(Locale):
    """
    01-01: [NF] Uudenvuodenpäivä
    01-06: [NRF] Loppiainen
    05-01: [NF] Vappu
    12-06: [NF] Itsenäisyyspäivä
    12-24: [NRF] Jouluaatto
    12-25: [NRF] Joulupäivä
    12-26: [NRF] 2. joulupäivä
    2 days before Easter: [NRV] Pitkäperjantai
    Easter: [NRV] Pääsiäispäivä
    1 day after Easter: [NRV] 2. pääsiäispäivä
    39 days after Easter: [NRV] Helatorstai
    49 days after Easter: [NRV] Helluntaipäivä
    : [NV] Juhannusaatto
    : [NV] Juhannuspäivä
    : [NV] Pyhäinpäivä
    """

    locale = "fi-FI"
    easter_type = EASTER_WESTERN

Checklist:

• Are all holidays (i.e. days "which are defined by law on which business or work are suspended or reduced") listed? Can you provide the legal sources which define the holidays?
• Is the spelling correct? Can you maybe provide a translation?
• Are the fixed dates <month>-<day> correct?
• If a holiday has a variable date: Is the algorithm to calculate it correct/can you provide it if missing? If it depends on the easter date: Is it the western or orthodox easter date?
• If a holiday is proclaimed by the government: Can you provide the source?
• Are holidays moved to a different date, e.g. if they fall on a saturday/sunday/...?
• Are holidays observed on a different date (is there a substitute holiday), e.g. if they fall on a saturday/sunday/...?
• Are the flags correct? (N = national holiday, defined by law, R = holiday with religious background, F = holiday with fixed date, V = holiday with variable date)
• Have there been any holidays renamed/deleted/created since 2011? If yes, which ones and since when?

[anttiheinonen]

Not sure about the ultimate official source, but https://almanakka.helsinki.fi/en/flag-days-and-holidays-in-finland.html is definately a very reputable one.
All the finnish translations can be found from https://almanakka.helsinki.fi/fi/liputus-ja-juhlapaivat/suomen-kalenterin-juhlapaivat.html, your list looks good to me.

[lauft]

Thank you for your input!

I have updated the fi-FI locale and it reproduces the available holidata from 2011 to 2018, so it's good to publish. The missing legal sources is a bit dissapointing; the wiki page lists Vuosilomalain 4 § as a source, but I could not find a distinct listing of holidays there - maybe later then.

From the data I also created the Swedish version (sv-FI) as well. 🐦🐦 + 🥌