Add more get routes

[rosesyrett]

Some functionality is missing which would be useful to have:

• getting the U/UB matrices directly.

This PR addresses this, but also modifies the routes for calculating ub and getting the status of it. Now the routes look like:

GET /ub/{name}/calculate - calculates the UB
GET /ub/{name}/ub - gets the UB matrix
GET /ub/{name}/u - gets the U matrix
GET /ub/{name}/status - gets the status of the UB object, i.e. a big string.

[callumforrester]

Looks good, just wondering why you've installed httpx when you already have requests

[rosesyrett]

Changed set_property route to:

• set_lab_reference_vector(XyzModel) & get_lab_reference_vector()
• set_miller_reference_vector(HklModel) & get_miller_reference_vector()
• set_lab_surface_normal(XyzModel) & get_lab_surface_normal()
• set_miller_surface_normal(HklModel) & get_miller_surface_normal()