Update docs with info about new timing manager system

[npetersen2]

Required before releasing v1.3.0.

TBD on what exactly needs to be changed on docs.amdc.dev...

Note from Patrick: Hey @annikaolson , don't forget to

• [x] Create a README for the timing manager IP core in its ip_repo folder

@codecubepi To-Do :

• [x] Update the docs pages about the AMDS interface and firmware here

[annikaolson]

I'm also going to need to update the following:

• https://github.com/Severson-Group/AMDC-Firmware/tree/v1.3-staging/ip_repo - add the timing manager in the IP blocks section

[codecubepi]

See docs repo #100.