update project name to 'legate-boost'

[jameslamb]

Contributes to #115.

Clarifies that the project name is legate-boost (with a -).

As of this PR, this project would have the following spellings.

Installation:

conda install legate-boost

pip install legate-boost

Python:

import legateboost

C++

namespace legateboost { ...

legateboost::PredictTask::register_variants();

Shared library:

liblegateboost.so

CMake:

project(legateboost ...

add_library(legateboost ...

Notes for Reviewers

I searched for these like this:

git grep -i legateboost

I choose to leave unchanged anything that seemed to be a reference to the project in general, not the Python package specifically.

For example:

legate-boost/docs/source/memory.md

Line 1 in 6487158

# Memory usage in Legateboost

legate-boost/legateboost/legateboost.py

Line 64 in 6487158

"LegateBoost does not currently support complex data."

Let me know if you think any of those should be changed too.