Support setting history file location with env variable

[ostrich]

The cht.sh config can be set with environment variable $CHTSH_CONF but a history file is still created in ~/.cht.sh/. Please consider supporting an environment variable for history as well.

[richardhttps]

Yes please!
What's up with apps loving to clutter the home directorY?

[abitrolly]

@richardhttps they just crave for attention.