Add ` hotkey to move to first line

[bhajneet]

Perhaps we should tweak this feature to skip manglacharan lines at the beginning or to be context aware of large shabads where the first line applies only to the 6-8 lines in the pauri, etc.

Another alternate idea is a hotkey for the first unread line as a dynamic hotkey.

[bhajneet]

Related #103

[Harjot1Singh]

Would this hotkey be different to home?

[bhajneet]

Home goes to the top most line regardless of whether it's a manglacharan or not

[bhajneet]

I also think a hotkey for "next unread line" could be powerful

[bhajneet]

After re-thinking this for a while, perhaps ` should be a hotkey same as home and the 1 key should be the first non-title line after the DB has implemented line types. This has a couple benefits: you can use the 1 key to go to the first "singing" line. You can do easier maths to find lines. If each pauri is 2 lines, you can easily know that 5 will be the start of the second or third set of lines.

Related to https://github.com/ShabadOS/database/issues/36

[bhajneet]

On hold until next DB major release and coupling with Desktop