Alpha: Dynamically check new name is valid

[kf106]

web/src/pages/HomePage/HomePage.tsx has an input field that shows the player's current name when they are logged in.

At the moment it is read only.

It should be writeable, and when they start editing the name, it should validate the content.

Local validation:

• only allow A-Z, a-z, 0-9, and _ in names
• Must be at least 2 characters long

Database validation:

• cannot be a name that is in the database for some other user (to stop people calling themselves BCGandalf, but more importantly, because the name is used to look up the address and hence the skin of the player)

I am guessing that this is similar to the orthoverse.io map name search functionality.

[kf106]

Implemented with kf106/clientNameValidation

https://www.youtube.com/watch?v=xauMVPim2Vk - here you can see names under 3 letters are rejected as are names containing unacceptable characters (border goes red), as are duplicate names (e.g. theotherguy), but my own name is not (bcgandalf)