gemtopbm, gemtopnm, pamtotga, ppmtotga, tgatoppm: add pages (#11402)

* gemtopbm, gemtopnm, pamtotga, ppmtotga, tgatoppm: add pages

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Co-authored-by: Sebastiaan Speck <12570668+sebastiaanspeck@users.noreply.github.com>

pages/common/pamtotga.md

@@ -0,0 +1,16 @@
+# pamtotga
+
+> Convert a Netpbm image to a TrueVision Targa file.
+> More information: <https://netpbm.sourceforge.net/doc/pamtotga.html>.
+
+- Convert a Netpbm image to a TrueVision Targa file:
+
+`pamtotga {{path/to/file.pam}} > {{path/to/output.tga}}`
+
+- Specify the color map of the output image:
+
+`pamtotga -{{cmap|cmap16|mono|rgb}} {{path/to/file.pam}} > {{path/to/output.tga}}`
+
+- Display version:
+
+`pamtotga -version`