Replace from_com and into_com with From implementations

[cgettys-microsoft]

Given that these from_com and into_com methods are all safe anyway, there's no good reason not to use From instead

Rewrite them as impl From<ITYPE> for TYPE and impl From<ITYPE> for TYPE.
In a few cases, the second (which would have been into_com before) did not exist, but made sense, so I added them.
As per general Rust guidance, implementing From, as that also results in the blanket Into implementation.

In the vast majority of cases, ownership was required, so I went with impl From<ITYPE> for TYPE instead of impl From<&ITYPE> for TYPE, as in some cases, this will save a reference count increment, and in the other case, it just moves where .clone is called, and those implementations won't be called frequently outside the library.

This also saved a few unnecessary clones inside the library that we appear to have had by accident.

Note in a few cases this makes it possible to construct the individual client wrappers outside the library (where we didn't have pub on from_com before). This is in my view a feature.

This will require any code outside this library to replace from_com with from and into_com with .into, but that shouldn't be a big deal.

I left FabricClient::from_com alone because the comment says the method is intended to be private eventually.

[OscarTHZhang]

msrustup is Microsoft internal toolchain. Shouldn't be reflected on a public open-source repo

[cgettys-microsoft]

Whoops, didn't mean to include that in this change, let me fix.

[cgettys-microsoft]

Fixed