feat(r8): Support rewriteFrames annotation in ProguardMapper

[romtsn]

Part of #63

• Added new header parsing
• Adapted ProguardMapper to ccollect the frames and then apply the rewrite rules on the entire vector
• Added parsing of the exception for remap_stacktrace which accepts a plain string -- we need that info to decide whether we remove inner frames or not

See linked issue for more details.

[loewenheim]

Approved by mistake

[loewenheim]

One minor improvement that can be made, otherwise this looks good.

[romtsn]

@loewenheim As discussed internally I implemented skipping the line completely if a rewrite rule cleared up all frames and also added a test to verify that: bb565b7

[loewenheim]

From my perspective this is good to merge