CSV export time format should be ISO with timezone

[markoaamunkajo]

Description:

CSV export time format should be ISO with timezone Let's add this to the export filename.

Android card: https://github.com/ruuvi/com.ruuvi.station/issues/1124 Web card: https://github.com/ruuvi/com.ruuvi.station.webui/issues/331

[markoaamunkajo]

@priyonto we decided to go with the full ISO format sorry.

Filename example: Friiz_2023-10-30T10:43:14+07:00

[priyonto]

@markoaamunkajo Slight problem here, on iOS file name can't have colon (:) in the name. Its replaced by '/'. We can have name without colon. For example: RuuviTag_2023-10-30T185727+0100

[markoaamunkajo]

@priyonto let's remove the lines as separator too and format like this:

RuuviTag_20230210T113000+0300

[markoaamunkajo]

QA passed