Add OLMo 1.7-7b README + Config

[2015aroras]

[dumitrac]

@2015aroras - do you think that for 1.7 we should have two configs? I understand that training was stopped, config changed, then resumed.

[soheeyang]

Hi, thank you so much for the work! Is there an estimated date of when all the details including the https links of the training data and the data order files are going to be released?

[2015aroras]

@kyleclo @soldni Do you have any updates on the data side?