[Feature requests] Allow to test the design's max speed

[zapta]

Currently the user needs to test manually the design speed using apio report. This request is for automatic tests that fails if the design doesn't meet the speed requirements. For example, the user specifies the min speeds in Mhz in apio.ini

min-freq =
   clk1:  12.00
   clk2:  42

and some existing (e.g. apio report) or a new command will exit with an error code if the speeds as reported by apio time are not met. The min-freq option should include exactly the list of clocks reported by apio report.

Also, existing methods such as apio build and apio upload can fail or emit a warning if the design goals are not met.

Another option is to add a clock-margin-percents apio.ini option such that they users can specify the nominal clock speeds but set a margin of let's say 20% from that speed. That is, if the clock is 12Mhz the design should handle 12Mhz + 20%.

Motivation:

• Creating user awareness if the design requirements are not met.
• Supporting automation.